Selective passivation and selective deposition

ABSTRACT

Methods for selective deposition, and structures thereof, are provided. Material is selectively deposited on a first surface of a substrate relative to a second surface of a different material composition. A passivation layer is selectively formed from vapor phase reactants on the first surface while leaving the second surface without the passivation layer. A layer of interest is selectively deposited from vapor phase reactants on the second surface relative to the passivation layer. The first surface can be metallic while the second surface is dielectric, or the second surface is dielectric while the second surface is metallic. Accordingly, material, such as a dielectric, can be selectively deposited on either metallic or dielectric surfaces relative to the other type of surface using techniques described herein. Techniques and resultant structures are also disclosed for control of positioning and shape of layer edges relative to boundaries between underlying disparate materials.

PRIORITY APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/892,728, filed Feb. 9, 2018, which claims priority to U.S.Provisional Application Nos. 62/458,952, filed Feb. 14, 2017;62/481,524, filed Apr. 4, 2017; and 62/591,724, filed Nov. 28, 2017, thedisclosures of each of these priority applications are herebyincorporated by reference herein in their entireties.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND Field

The present disclosure relates generally to selective deposition ofmaterials on a first surface of a substrate relative to a second surfaceof a different material composition.

Description of the Related Art

The shrinking device dimensions in semiconductor manufacturing call fornew innovative processing approaches. Conventionally, patterning insemiconductor processing involves subtractive processes, in whichblanket layers are deposited, masked by photolithographic techniques,and etched through openings in the mask. Additive patterning is alsoknown, in which masking steps precede deposition of the materials ofinterest, such as patterning using lift-off techniques or damasceneprocessing. In most cases, expensive multi-step lithographic techniquesare applied for patterning.

Patterning could be simplified by selective deposition, which has gainedincreasing interest among semiconductor manufacturers. Selectivedeposition would be highly beneficial in various ways. Significantly, itcould allow a decrease in lithography steps, reducing the cost ofprocessing. Selective deposition could also enable enhanced scaling innarrow structures, such as by making bottom up fill possible.Electrochemical deposition is one form of selective deposition, asmetals can be formed selectively on conductive elements. Chemical vapordeposition (CVD) and atomic layer deposition (ALD) are surface-sensitivetechniques vapor deposition techniques and therefore have beeninvestigated as good candidates for selective deposition. Selective ALDwas suggested, for example, in U.S. Pat. No. 6,391,785.

One of the challenges with selective deposition is selectivity fordeposition processes are often not high enough to accomplish the goalsof selectivity. Surface pre-treatment is sometimes available to eitherinhibit or encourage deposition on one or both of the surfaces, butoften such treatments themselves call for lithography to have thetreatments applied or remain only on the surface to be treated.

Accordingly, a need exists for more practical processes foraccomplishing selective deposition.

SUMMARY OF THE INVENTION

In one aspect a method is provided for selective deposition on a secondsurface of a part relative to a first surface of the part, where thefirst and second surfaces have different compositions. The methodincludes selectively forming a passivation layer from vapor phasereactants on the first surface while leaving the second surface withoutthe passivation layer. The method further includes selectivelydepositing a layer of interest from vapor phase reactants on the secondsurface relative to the passivation layer.

In some embodiments, the method of selectively forming the passivationlayer further includes etching any polymer from the second surface whileleaving some polymer on the first surface. In some embodiments, themethod includes an edge of the layer of interest aligned with a boundarybetween the first and second surfaces. In some embodiments, the methodincludes the layer of interest overlapping with the first surface. Insome embodiments, the method includes the first surface elevated abovethe second surface. In some embodiments, after removing the passivationlayer, the method includes a gap exposing the second surface existsbetween an edge of the layer of interest and a boundary between thefirst and second surfaces. In some embodiments, the method furtherincludes selectively etching the second surface in the gap to form acavity. In some embodiments, the method further includes depositing acavity filling material in a manner that leaves an air-gap within thecavity.

In another aspect an apparatus is provided for organic layer deposition.The apparatus includes a first vessel configured for vaporizing a firstorganic reactant to form a reactant vapor and a second vessel configuredfor vaporizing a second organic reactant to form a reactant vapor. Theapparatus further includes a plasma source communicating with hydrogenand inert gas sources and a reaction space configured to accommodate asubstrate and in selective fluid communication with the first and secondvessels. A control system is configured to deposit an organic layer onthe substrate by communicating vapors from the first and second vessels,and to etch back the organic layer by operating the plasma source.

In another aspect an integrated circuit metallization structure isprovided. The structure includes a metallic feature at least partiallyembedded within the low k material, a low k material, and a dielectricetch stop material. The structure further includes an air-gap positionedwithin the low k material and positioned adjacent to a lateral side ofthe metallic feature.

In another aspect an integrated circuit metallization structure isprovided. The structure includes a low k material and a metallic featureat least partially embedded within the low k material. The structurefurther includes a dielectric etch stop material overlying the low kmaterial, wherein the dielectric etch stop material comprises an edgeprofile characteristic of a selectively deposited material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic cross section of a portion of a substrate havingfirst and second surfaces of different compositions, in accordance witha first embodiment.

FIG. 1B is a schematic cross section of the substrate of FIG. 1A after aselective passivation of the first surface.

FIG. 1C is a schematic cross section of the substrate of FIG. 1B afterselective deposition on the second surface.

FIG. 1D is a schematic cross section of the substrate of FIG. 1C afterremoval of the passivation material from the first surface.

FIG. 2A is a schematic cross section of a portion of a substrate havingfirst and second surfaces of different compositions, with a passivationblocking material formed on the second surface, in accordance with asecond embodiment.

FIG. 2B is a schematic cross section of the substrate of FIG. 2A after aselective passivation of the first surface.

FIG. 2C is a schematic cross section of the substrate of FIG. 2B afterremoval of the passivation blocking material from the second surface.

FIG. 2D is a schematic cross section of the substrate of FIG. 2C afterselective deposition on the second surface.

FIG. 2E is a schematic cross section of the substrate of FIG. 2D afterremoval of the passivation material from the first surface.

FIG. 3A is a schematic cross section of the substrate of FIG. 2D afterselective deposition of a further material over the second surface, inaccordance with a third embodiment.

FIG. 3B is a schematic cross section of the substrate of FIG. 3A afterremoval of the passivation material from the first surface.

FIG. 4A is a flow diagram generally illustrating processes forselectively depositing an organic passivation layer.

FIG. 4B is a flow diagram generally illustrating atomic layer deposition(ALD) processes for selectively depositing an organic layer.

FIG. 5 is a graph illustrating selectivity of a zirconium oxide atomiclayer deposition (ALD) process on a native oxide surface relative to apolymer surface.

FIG. 6 is graph illustrating titanium oxide thickness over native oxideas a function of cycle numbers and deposition temperatures for atitanium oxide ALD process.

FIG. 7 is a graph illustrating titanium oxide thickness over polymer asa function of cycle numbers and deposition temperatures for a titaniumoxide ALD process.

FIG. 8 is a bar graph illustrating water contact angle vs. time ofexposure to a vapor precursor for a sulfur-containing self-assembledmonolayer (SAM).

FIG. 9 is a micrograph illustrating water contact angle over asulfur-containing SAM formed after hydrochloric acid (HCl) pretreatment.

FIG. 10 is a micrograph illustrating water contact angle over asulfur-containing SAM formed after formic acid (HCOOH) pretreatment.

FIG. 11 is a bar graph illustrating water contact angle over a coppersurface after exposure to deposition processes for sulfur-containing SAMand/or polymer.

FIG. 12 is a bar graph illustrating material composition by XPS analysisfor various materials after exposure to a polymer deposition process.

FIG. 13 is a table illustrating material composition for variousmaterial surfaces after exposure to 100 or 250 cycles of a polymer ALDprocess.

FIG. 14 is a micrograph illustrating water contact angle over a coppersurface after exposure to a deposition process for a sulfur-containingSAM.

FIG. 15 is a micrograph illustrating water contact angle over aninorganic dielectric surface after exposure to the deposition processfor the sulfur-containing SAM.

FIG. 16 is a schematic illustration of an apparatus configured forselective deposition of a polymer layer and in situ etch back fromundesired surfaces.

FIG. 17 is a flow diagram generally illustrating processes forselectively depositing a dielectric layer on second surfaces afterselective passivation of first surfaces with organic material inaccordance with embodiments.

FIG. 18 is a flow diagram utilizing schematic cross sections of aportion of a substrate having first and second surfaces of differentcompositions, and generally illustrates the effect that the extent ofetch back on the passivation material has on the relationship of thedielectric layer formed with the interface of the first and secondsurfaces.

FIG. 19 is a flow diagram utilizing schematic cross sections of aportion of a substrate having first and second surfaces of differentcompositions, and generally illustrates the effect passivation layerthickness has on the relationship of the dielectric layer formed withthe interface of the first and second surfaces.

FIG. 20 is a flow diagram utilizing schematic cross sections of aportion of a substrate having first and second surfaces of differentcompositions, and generally illustrates the effect dielectric thicknesshas on the relationship of the dielectric layer formed with theinterface of the first and second surfaces.

FIG. 21A is a schematic cross section of a portion of substrate havingflush first and second surfaces of different compositions withpassivation and dielectic layers selectively deposited thereover,respectively.

FIG. 21B is a schematic cross section of a portion of substrate havingfirst and second surfaces of different compositions with the firstsurfaces recessed relative to the second surfaces and passivation anddielectic layers selectively deposited thereover, respectively.

FIG. 21C is a schematic cross section of a portion of substrate havingfirst and second surfaces of different compositions with first surfaceselevated relative to the second surfaces and with passivation anddielectric layers selectively deposited thereover, respectively.

FIG. 21D is a schematic cross section of a portion of substrate havingfirst and second surfaces of different compositions with first surfacesrecessed relative to the second surfaces and with passivation anddielectric layers selectively deposited thereover, respectively.

FIG. 22A is a schematic cross section of a portion of a substrate withan embedded metal feature.

FIG. 22B is a schematic cross section of the substrate of FIG. 22A afterformation of a metal cap to define a first surface.

FIG. 22C is a schematic cross section of the substrate of FIG. 22B afterselective passivation deposition and etch back, leaving a passivationfilm over the metal cap with edges of the metal cap exposed.

FIG. 22D is a schematic cross section of the substrate of FIG. 22C afterselective deposition of a dielectric material over low k surfaces of thesubstrate, where the deposited dielectric resists etching of low kmaterials and overlaps with the metal cap.

FIG. 22E is a schematic cross section of the substrate of FIG. 22D afterremoval of the passivation layer.

FIG. 23A is a flow diagram showing schematic cross sections of a portionof a substrate having first and second surfaces of differentcompositions, and generally illustrates selective passivation of thefirst surfaces, etch back in a manner that leaves the passivationoverlapping with the second surfaces, and selective deposition of adielectric etch mask on the remainder of the second surfaces.

FIG. 23B are schematic cross sections of the substrate of FIG. 23A,following removal of the passivation layers, leaving gaps between thefirst surfaces and the dielectric etch mask, selective etching of thelow k material exposed in the gaps, and deposition to leave air-gapswithin the substrate.

FIG. 24 is a graph illustrating polymer thickness as a function ofetching pulses for three different etching temperatures using O₃ as anetchant.

FIG. 25 is a graph illustrating the Arrhenius plot of etch rate as afunction of inverse temperature for O₃ etching of a polymer.

DETAILED DESCRIPTION OF EMBODIMENTS

Methods and apparatus are disclosed for selectively depositing materialover a second surface relative to a first surface, where the first andsecond surfaces have material differences. For example, one of thesurfaces can include a metallic material and the other surface caninclude an inorganic dielectric material. In embodiments describedherein, an organic passivation layer is deposited selectively on thefirst surface relative to the second surface. In some embodiments, thefirst surface is metallic and the second surface is dielectric; in otherembodiments the first surface is dielectric and second surface ismetallic. Subsequently, a layer of interest is selectively deposited onthe second surface relative to the organic passivation layer. Furtherlayers can be selectively deposited on the layer of interest, oversecond surface, relative to the organic passivation layer.

In one embodiment, the first surface comprises a metallic surface, suchas an elemental metal or metal alloy, while the second surface comprisesan inorganic dielectric surface, such as low-k material. Examples oflow-k material include silicon oxide based materials, including grown ordeposited silicon dioxide, doped and/or porous oxides, native oxide onsilicon, etc. A polymer passivation layer is selectively deposited onthe metallic surface relative to the inorganic dielectric surface.Subsequently, a layer of interest is selectively deposited on theinorganic dielectric surface. The layer of interest may include a metalelement. Examples of the layer of interest include dielectrics, such aszirconium oxide (e.g., ZrO₂), hafnium oxide (e.g., HfO₂) and titaniumoxide (e.g., TiO₂). Processes are provided for selectively depositingsuch materials on silicon-oxide based surfaces relative to polymersurfaces.

In a second embodiment, the first surface comprises an inorganicdielectric surface, such as low-k material, while the second surfacecomprises a metallic surface, such as an elemental metal or metal alloy.Examples of low-k material include silicon oxide based materials,including grown or deposited silicon dioxide, doped and/or porousoxides, native oxide on silicon, etc. A polymer passivation layer isselectively deposited on the inorganic dielectric surface relative tometallic surface. Prior to depositing the polymer passivation layer, themetallic surface can be provided with a passivation blocking layer, suchas a self-assembled monolayer (SAM). The passivation blocking layerfacilitates selectivity for the polymer deposition on inorganicdielectric surface, and can be removed thereafter to permit selectivedeposition of a layer of interest on the metallic surface relative tothe polymer passivation layer. The layer of interest may include a metalelement. Examples of the layer of interest include metal layers (e.g.,see U.S. Pat. No. 8,956,971, issued Feb. 17, 2015 and U.S. Pat. No.9,112,003, issued Aug. 18, 2015) and metal oxide layers (e.g., zirconiumoxide, hafnium oxide, titanium oxide). Processes are provided forselectively depositing such materials on metallic surfaces relative topolymer surfaces.

In a third embodiment, the process of the second embodiment is conductedto provide a layer of interest selectively over a metallic surfacerelative to a polymer-passivated inorganic dielectric surface.Thereafter, a further layer of interest is selectively deposited overthe layer of interest while the polymer remains passivating theinorganic dielectric surface. For example, the layer of interest maycomprise a metal layer while the further layer of interest comprises ametal oxide layer (e.g., zirconium oxide, hafnium oxide, titaniumoxide). Processes are provided for selectively depositing such materialson metallic surfaces relative to polymer surfaces.

The polymer passivation layer may be removed from the first surfacefollowing selective deposition of the layer(s) of interest over thesecond surface. For example, oxidation processes may selectively removepolymer materials. Conditions are chosen to avoid damage to surroundingmaterials on the substrate.

Embodiments are also provided for controlling the edge profiles and edgepositions for selectively deposited layers relative to other features onthe substrate, such as the boundaries between underlying metallic anddielectric surfaces. Accordingly, control is provided over relativepositioning of selective layer edges without the need for expensivelithographic patterning. Examples illustrate applications for suchcontrol, including examples in which the selective layer overlaps thematerial on which deposition is minimized; examples in which theselective layer is formed with a gap spacing the layer from the materialon which deposition is minimized; and examples in which the edge of theselective layer aligns with the boundary between the two disparateunderlying materials.

Substrate Surfaces

According to some aspects of the present disclosure, selectivedeposition can be used to deposit films of interest on a second surfacepreferentially relative to a first surface. The two surfaces can havedifferent material properties that permit selective formation of anorganic material thereon, such as selective deposition of a polymerlayer on the first surface relative to the second surface, which in turnpermits subsequent selective deposition of a layer of interest on thesecond surface relative to the organic-passivated first layer.

For example, in embodiments described herein, one of the surfaces can bea conductive (e.g., metal or metallic) surface of a substrate, while theother surface can be a non-conductive (e.g., inorganic dielectric)surface of the substrate. In some embodiments, the non-conductivesurface comprises —OH groups, such as a silicon oxide-based surface(e.g., low-k materials, including grown and deposited silicon-oxidematerials and native oxide over silicon). In some embodiments thenon-conductive surface may additionally comprise —H terminations, suchas an HF dipped Si or HF dipped Ge surface. In such embodiments, thesurface of interest will be considered to comprise both the —Hterminations and the material beneath the —H terminations

For any of the examples noted above, the material differences betweenthe two surfaces are such that vapor deposition methods can selectivelydeposit the organic passivation layer on the first surface relative tothe second surface. In some embodiments, cyclical vapor deposition isused, for example, cyclical CVD or atomic layer deposition (ALD)processes are used. In some embodiments, selectivity for the organicpassivation layer can be achieved without passivation/blocking agents onthe surface to receive less of the organic layer; and/or withoutcatalytic agents on the surface to receive more of the organic layer.For example, in embodiments where the first surface is metallic and thesecond surface is dielectric, polymers can be selectively depositeddirectly on metallic surfaces relative to inorganic dielectric surfaces.In other embodiments, where the first surface is dielectric and thesecond surface is metallic, the second surface is first treated toinhibit polymer deposition thereover. For example, a passivationblocking self-assembled monolayer (SAM) can be first formed over ametallic surface relative, facilitating selective deposition of apolymer passivation layer on a dielectric surface, such as an inorganicdielectric surface, relative to a SAM-covered second metallic surface.After selective deposition of the organic passivation is completed,further selective deposition of materials of interest, such as metaloxide or metal layers, can be conducted on the non-passivated secondsurface relative to the passivated first surface.

For embodiments in which one surface comprises a metal whereas the othersurface does not, unless otherwise indicated, if a surface is referredto as a metal surface herein, it may be a metal surface or a metallicsurface. In some embodiments, the metal or metallic surface may comprisemetal, metal oxides, and/or mixtures thereof. In some embodiments, themetal or metallic surface may comprise surface oxidation. In someembodiments, the metal or metallic material of the metal or metallicsurface is electrically conductive with or without surface oxidation. Insome embodiments, metal or a metallic surface comprises one or moretransition metals. In some embodiments, the metal or metallic surfacecomprises one or more of Al, Cu, Co, Ni, W, Nb, Fe, or Mo. In someembodiments, a metallic surface comprises titanium nitride. In someembodiments, the metal or metallic surface comprises one or more noblemetals, such as Ru. In some embodiments, the metal or metallic surfacecomprises a conductive metal oxide, nitride, carbide, boride, orcombination thereof. For example, the metal or metallic surface maycomprise one or more of RuO_(x), NbC_(x), NbB_(X), NiO_(x), CoO_(x),NbO_(x), MoO_(x), WO_(x), WNC_(x), TaN, or TiN.

In some embodiments, a metal or metallic surface comprises cobalt (Co),copper (Cu), tungsten (W) or molybdenum (Mo). In some embodiments, themetal or metallic surface may be any surface that can accept orcoordinate with the first or second precursor utilized in a selectivedeposition process of either the organic passivation layer or the layerof interest, as described herein, depending upon the embodiment.

In some embodiments, an organic passivation material is selectivelydeposited on a metal oxide surface relative to other surfaces. A metaloxide surface may be, for example a WO_(x), TiO_(x), surface. In someembodiments, a metal oxide surface is an oxidized surface of a metallicmaterial. In some embodiments, a metal oxide surface is created byoxidizing at least the surface of a metallic material using oxygencompound, such as compounds comprising O₃, H₂O, H₂O₂, O₂, oxygen atoms,plasma or radicals or mixtures thereof. In some embodiments, a metaloxide surface is a native oxide formed on a metallic material.

In some embodiments, the second surface may comprise a metal surfaceincluding a passivation block layer thereover. That is, in someembodiments, the second surface may comprise a metal surface comprisinga material that inhibits deposition of the passivation layer thereover,for example a self-assembled monolayer (SAM).

In some embodiments, an organic passivation material is selectivelydeposited on a first metal oxide surface, which is an oxidized surfaceof metallic material, relative to a second dielectric surface

In some embodiments, one of the first and second surfaces is a metal ormetallic surface of a substrate and the other surface is a dielectricsurface of the substrate. The term dielectric is used in the descriptionherein for the sake of simplicity in distinguishing from the othersurface, namely the metal or metallic surface. It will be understood bythe skilled artisan that not all non-conducting surfaces are dielectricsurfaces, and conversely not all metallic surfaces are conducting. Forexample, the metal or metallic surface may comprise an oxidized metalsurface that is electrically non-conducting or has a very highresistivity. Selective deposition processes taught herein can deposit onsuch non-conductive metallic surfaces with minimal deposition onpassivated dielectric surfaces and similarly selective depositionprocesses can deposit on dielectric surfaces with minimal deposition onpassivated non-conductive metallic surfaces.

In some embodiments, the substrate may be pretreated or cleaned prior toor at the beginning of the selective deposition process. In someembodiments, the substrate may be subjected to a plasma cleaning processat prior to or at the beginning of the selective deposition process. Insome embodiments, a plasma cleaning process may not include ionbombardment, or may include relatively small amounts of ion bombardment.For example, in some embodiments the substrate surfaces may be exposedto plasma, radicals, excited species, and/or atomic species prior to orat the beginning of the selective passivation layer deposition process.In some embodiments, the substrate surface may be exposed to hydrogenplasma, radicals, or atomic species prior to or at the beginning of theselective passivation layer deposition process. In some embodiments, apretreatment or cleaning process may be carried out in the same reactionchamber as a selective deposition process, however in some embodiments apretreatment or cleaning process may be carried out in a separatereaction chamber.

Selectivity

The skilled artisan will appreciate that selective deposition can befully selective or partially selective. A partially selective processcan result in fully selective layer by a post-deposition etch thatremoves all of the deposited material from over surface B withoutremoving all of the deposited material from over surface A. Because asimple etch back process can leave a fully selective structure withoutthe need for expensive masking processes, the selective deposition neednot be fully selective in order to obtain the desired benefits.

Selectivity of deposition on surface A relative to surface B can begiven as a percentage calculated by [(deposition on surfaceA)−(deposition on surface B)]/(deposition on the surface A). Depositioncan be measured in any of a variety of ways. For example, deposition maybe given as the measured thickness of the deposited material, or may begiven as the measured amount of material deposited. In embodimentsdescribed herein, selective deposition of an organic passivation layercan be conducted on a first surface (A) relative to a second surface(B). Subsequently, a layer of interest is selectively deposited on thesecond surface (A) relative to the organic passivation layer (B) overthe first surface.

In some embodiments, selectivity for the selective deposition of thepassivation layer on the first surface (relative to the second surface)and/or selectivity of the layer of interest on the second surface(relative to the passivation layer on the first surface) is greater thanabout 10%, greater than about 50%, greater than about 75%, greater thanabout 85%, greater than about 90%, greater than about 93%, greater thanabout 95%, greater than about 98%, greater than about 99% or evengreater than about 99.5%. In embodiments described herein, theselectivity for the organic passivation layer deposition can change overthe duration or thickness of a deposition. Surprisingly, selectivity hasbeen found to increase with the duration of the deposition for the vaporphase polymer layer depositions described herein. In contrast, typicalselective deposition based on differential nucleation on differentsurfaces tends to become less selective with greater duration orthickness of a deposition.

In some embodiments, deposition only occurs on the first surface anddoes not occur on the second surface. In some embodiments, deposition onsurface A of the substrate relative to surface B of the substrate is atleast about 80% selective, which may be selective enough for someparticular applications. In some embodiments, the deposition on thesurface A of the substrate relative to surface B of the substrate is atleast about 50% selective, which may be selective enough for someparticular applications. In some embodiments the deposition on surface Aof the substrate relative to the surface B of the substrate is at leastabout 10% selective, which may be selective enough for some particularapplications. The skilled artisan will appreciate that a partiallyselective process can result in fully selective structure layer by apost-deposition etch that removes all of the deposited material fromover surface B without removing all of the deposited material from oversurface A. Furthermore, the post-deposition etch can also aid intailoring the position and/or profile of the selectively depositedlayer, as will be better understood from the description of FIGS. 17-23Bbelow.

In some embodiments, the organic layer deposited on the first surface ofthe substrate may have a thickness less than about 50 nm, less thanabout 20 nm, less than about 10 nm, less than about 5 nm, less thanabout 3 nm, less than about 2 nm, or less than about 1 nm, while a ratioof material deposited on the first surface of the substrate relative tothe second surface of the substrate may be greater than or equal toabout 200:1, greater than or equal to about 100:1, greater than or equalto about 50:1, greater than or equal to about 25:1, greater than orequal to about 20:1, greater than or equal to about 15:1, greater thanor equal to about 10:1, greater than or equal to about 5:1, greater thanor equal to about 3:1, or greater than or equal to about 2:1.

In some embodiments the selectivity of the selective depositionprocesses described herein may depend on the material compositions ofthe materials which define the first and/or second surface of thesubstrate. For example, in some embodiments where the first surfacecomprises a BTA passivated Cu surface and the second surface comprises anatural or chemical silicon dioxide surface the selectivity may begreater than about 8:1 or greater than about 15:1. In some embodiments,where the first surface comprises a metal or metal oxide and the secondsurface comprises a natural or chemical silicon dioxide surface theselectivity may be greater than about 5:1 or greater than about 10:1.

Selective Deposition on Dielectric

FIGS. 1A-1D schematically illustrate a first embodiment for selectivepassivation of a first surface relative to a second surface, followed byselective deposition on the second surface relative to the passivatedfirst surface. In the illustrated embodiment, the first surfacecomprises a metallic material; the second surface comprises an inorganicdielectric material; and the material of interest deposited on thesecond surface comprises a dielectric material.

FIG. 1A illustrates a substrate having materially different surfacesexposed. For example, the first surface can comprise or be defined by ametal, such as cobalt (Co), copper (Cu), tungsten (W) or molybdenum(Mo). The second surface can comprise or be defined by an inorganicdielectric, such as a low-k layer (typically a silicon oxide-basedlayer) or a silicon surface having native oxide (also a form of siliconoxide) formed thereover.

FIG. 1B shows the substrate of FIG. 1A after selective deposition of apassivation layer over the first surface. For example, the passivationlayer may be a polymer layer deposited selectively on the metallicsurface of the first layer. Methods for selectively depositing polymerlayers by vapor deposition techniques are disclosed in U.S. patentapplication Ser. No. 15/170,769, filed Jun. 1, 2016, the entiredisclosure of which is incorporated herein by references for allpurposes. Further information and examples of selective deposition ofpolymer layers to serve as the passivation layer are provided below.

In some embodiments, the selectively deposited polymer is a polyimide.In some embodiments, the polymer deposited is a polyamide. Otherexamples of deposited polymers include dimers, trimers, polyurea layers,polythiophene polyurethanes, polythioureas, polyesters, polyimines,other polymeric forms or mixtures of the above materials. Vapordeposited organic materials include polyamic acid, which may be aprecursor to polymer formation. The selectively deposited layer can be amixture including polymer and polyamic acid, which for purposes of thepresent disclosure will be considered to be a polymer.

As noted above, any organic material deposited on the second surface (aninorganic dielectric surface in this example) can be removed by an etchback process. In some embodiments, an etch process subsequent toselective deposition of the organic layer may remove deposited organicmaterial from both the first surface and the second surface of thesubstrate. In some embodiments the etch process may be isotropic.

In some embodiments, the etch process may remove the same amount, orthickness, of material from the first and second surfaces. That is, insome embodiments the etch rate of the organic material deposited on thefirst surface may be substantially similar to the etch rate of theorganic material deposited on the second surface. Due to the selectivenature of the deposition processes described herein, the amount oforganic material deposited on the second surface of the substrate issubstantially less than the amount of material deposited on the firstsurface of the substrate. Therefore, an etch process may completelyremove deposited organic material from the second surface of thesubstrate while deposited organic material may remain on the firstsurface of the substrate. Suitable processes for etching polymers aredescribed below with respect to FIG. 1D.

FIG. 1C shows the substrate of FIG. 1B following selective deposition ofa layer of interest X on the second surface (an inorganic dielectricsurface in this example) relative to the passivation layer on the firstsurface (a metallic surface in this example). The layer of interest Xcan be a dielectric material, particularly a metal oxide such aszirconium oxide, hafnium oxide or titanium oxide. Methods forselectively depositing such metal oxide layers by vapor depositiontechniques, employing hydrophobic precursors to aid selectivity relativeto organic passivation layers, are disclosed in U.S. provisional patentapplication No. 62/332,396, filed May 5, 2016, the entire disclosure ofwhich is incorporated herein by references for all purposes. Furtherinformation and examples of selective deposition of metal oxide andother layers of interest are provided below.

As noted above, any X material deposited on the passivation layer overthe first surface can be removed by an etch back process. Because thelayer of interest is deposited selectively on the second surface, any Xmaterial left on the passivation surface will be thinner than thepassivation layer formed on the metallic surface. Accordingly, the etchback process can be controlled to remove all of the X material over thepassivation layer without removing all of the layer of interest fromover the dielectric surface. Repeatedly depositing selectively andetching back in this manner can result in an increasing thickness of theX material on the dielectric with each cycle of deposition and etch.Repeatedly depositing selectively and etching back in this manner canalso result in increased overall selectivity of the X material on thedielectric, as each cycle of deposition and etch leaves a cleanpassivation layer over which the selective X deposition nucleatespoorly. Alternatively, any X material can be removed during subsequentremoval of the passivation layer, example conditions for which aredescribed with respect to FIG. 1D below, in a lift-off process. As isknown in the art, a lift-off process removes an overlying material byundercutting with removal of an underlying material. Any X materialformed on the passivation layer in a short selective deposition processtends to be noncontinuous, allowing access of the etchant to theunderlying material to be removed. The lift-off etch need not fullyremove the passivation layer in order to remove all of the undesired Xmaterial from the passivation layer surface, such that either a directetch or the lift-off method can be used to remove the X material fromthe passivation layer surface in a cyclical selective deposition andremoval.

FIG. 1D shows the substrate of FIG. 1C after removal of the passivationlayer from the first surface. In some embodiments, the etch process maycomprise exposing the substrate to a plasma. In some embodiments, theplasma may comprise oxygen atoms, oxygen radicals, oxygen plasma, orcombinations thereof. In some embodiments, the plasma may comprisehydrogen atoms, hydrogen radicals, hydrogen plasma, or combinationsthereof (see, e.g., Example 2 for selective deposition of passivationlayer below). In some embodiments, the plasma may also comprise noblegas species, for example Ar or He species. In some embodiments theplasma may consist essentially of noble gas species. In some instances,the plasma may comprise other species, for example nitrogen atoms,nitrogen radicals, nitrogen plasma, or combinations thereof. In someembodiments, the etch process may comprise exposing the substrate to anetchant comprising oxygen, for example O₃. In some embodiments, thesubstrate may be exposed to an etchant at a temperature of between about30° C. and about 500° C., preferably between about 100° C. and about400° C. In some embodiments, the etchant may be supplied in onecontinuous pulse or may be supplied in multiple shorter pulses. As notedabove, the passivation layer removal can be used to lift-off anyremaining X material from over the passivation layer, either in acomplete removal of the passivation layer or in a partial removal of thepassivation layer in a cyclical selective deposition and removal.

As noted above, in some embodiments, O₃ (e.g. O₃/N₂) can be used in theetch process for removal of the organic passivation layer. In someembodiments, the etch process may be performed at a substratetemperature of about 20° C. to about 500° C. In some embodiments, theetch process may be performed at a substrate temperature of about 50° C.to about 300° C. In some embodiments, the etch process may be performedat a substrate temperature of about 100° C. to about 250° C. In someembodiments, the etch process may be performed at a substratetemperature of about 125° C. to about 200 C. In some embodiments, theetch process may be performed at a rate of about 0.05 nm/min to about50.0 nm/min. In some embodiments, the etch process may be performed at arate of about 0.1 nm/min to about 5.0 nm/min. In some embodiments, theetch process may be performed at a rate of about 0.2 nm/min to about 2.5nm/min. In some embodiments for single wafer or small batch (e.g., 5wafers or less) processing, a low O₃ concentration etch process may beused, wherein the low O₃ concentration etch process is performed at 0.01Torr to 200 Torr, more particularly about 0.1 Torr to 100 Torr (e.g., 2Torr). Etchant pulsing can be between 0.01 sec and 20 seconds,particularly between 0.05 sec and 10 sec, even more particularly between0.1 sec and 2 seconds (e.g., 0.5 sec pulse/0.5 sec purge of O₃). O₃ flowcan range from 0.01 slm to 1 slm, more particularly from 0.01 slm to0.250 slm. Inert (e.g., N₂) carrier gas flow of can range from 0.1 slmto 20 slm, more particularly from 0.5 slm to 5 slm (e.g., 1.2 slm). Insome embodiments, a high O₃ concentration etch process may be used,wherein the high O₃ concentration etch process is performed at 1-100Torr, more particularly 5-20 Torr (e.g., 9 Torr), with longer exposuresper cycle. For example, O₃ exposure times can be between 0.1 sec and 20s, more particularly between 0.5 sec and 5 seconds (e.g., 1 sec pulse/1sec purge of O₃). O₃ flow for such high 03 concentration processes canbe between 0.1 slm and 2.0 slm, more particularly between 0.5 slm and1.5 slm (e.g, 750 sccm), with an inert (e.g., N₂) dilution flow of 0.1slm to 20 slm, more particularly 0.5 slm to 5 slm (e.g., 1.2 slm).Further description of O₃ etch processes are provided below withreference to FIGS. 24 and 25.

Additional treatments, such as heat or chemical treatment, can beconducted prior to, after or between the foregoing processes. Forexample, treatments may modify the surfaces or remove portions of themetal, silicon oxide, polymer passivation and metal oxide surfacesexposed at various stages of the process. In some embodiments thesubstrate may be pretreated or cleaned prior to or at the beginning ofthe selective deposition process. In some embodiments, the substrate maybe subjected to a plasma cleaning process at prior to or at thebeginning of the selective deposition process. In some embodiments, aplasma cleaning process may not include ion bombardment, or may includerelatively small amounts of ion bombardment. For example, in someembodiments the substrate surface may be exposed to plasma, radicals,excited species, and/or atomic species prior to or at the beginning ofthe selective deposition process. In some embodiments, the substratesurface may be exposed to hydrogen plasma, radicals, or atomic speciesprior to or at the beginning of the selective deposition process. Insome embodiments, a pretreatment or cleaning process may be carried outin the same reaction chamber as a selective deposition process, howeverin some embodiments a pretreatment or cleaning process may be carriedout in a separate reaction chamber.

Selective Deposition on Metal

FIGS. 2A-2E illustrate schematically illustrate a second embodiment forselective passivation of a first surface relative to a second surface,followed by selective deposition on the second surface relative to thepassivated first surface. In the illustrated embodiment, the firstsurface comprises an inorganic dielectric material; the second surfacecomprises a metallic surface; and the material of interest deposited onthe second surface comprises a dielectric material or a metal.

FIG. 2A illustrates a substrate similar to that of FIG. 1A, havingmaterially different surfaces. For this embodiment, however, thesurfaces are described with reversed terminology. In particular, thesecond surface can comprise or be defined by a metallic material, suchas cobalt (Co), copper (Cu), tungsten (W) or molybdenum (Mo). The firstsurface can comprise an inorganic dielectric, such as a low-k layer(typically a silicon oxide-based layer) or a silicon surface havingnative oxide (also a form of silicon oxide) formed thereover. Apassivation blocking layer is formed over the second surface. Note thatthe term “blocking” is not meant to imply that the subsequent selectivedeposition of a passivation layer is completely blocked by thepassivation blocking layer. Rather, the passivation blocking layer overthe second surface need only inhibit the deposition of the passivationlayer to have a lower growth rate relative to the growth rate over thefirst surface.

In one embodiment, the passivation blocking layer comprises aself-assembled monolayer (SAM). Preferably SAM can be selectively formedover the second (metallic) surface without forming on the first(dielectric) surface. Advantageously, sulfur-containing SAM has beenfound particularly effective to minimize deposition of the passivationlayer thereover, as discussed with respect to FIGS. 11-13 below. Furtherdetails on the formation of sulfur-containing SAM, employingvapor-delivered 1-dodecanaethiol (CH₃(CH₂)₁₁SH), are discussed withrespect to FIGS. 8-10 and 14-15 below.

FIG. 2B shows the selective formation of a passivation layer (e.g.,organic passivation layer) over the first surface, in this case theinorganic dielectric layer, relative to the passivation blocking layerover the second surface. As noted in the above incorporated patentapplication Ser. No. 15/170,769, filed Jun. 1, 2016, vapor depositionprocesses described therein are capable of depositing polymer oninorganic dielectrics, and can even deposit selectively (i.e., atdifferential deposition rates) over different types of silicon oxide. Inthe present embodiment, sulfur-containing SAM inhibits the polymerdeposition thereover, such that polymer can selectively form over thefirst surface, and can serve as a passivation layer against a subsequentdeposition.

FIG. 2C shows the substrate of FIG. 2B after removal of the passivationblocking layer from over the second surface. For example,sulfur-containing SAM material can be removed by heat treatment attemperatures lower than those that would remove a polymer layer likepolyimide. Accordingly, a passivation layer is left selectively over thefirst surface, while the second surface is exposed. The structure issimilar to that of FIG. 1B except that the first passivated surface isan inorganic dielectric in this embodiment, and the second surface is ametallic surface.

FIG. 2D shows the substrate of FIG. 2C after selective deposition of alayer of interest X on the second surface relative to the passivationlayer over the first surface. As noted with respect to the firstembodiment, and described in the above-incorporated provisional patentapplication No. 62/332,396, filed May 5, 2016, metal oxides can beselectively deposited using vapor deposition techniques and hydrophobicprecursors to aid selectivity relative to organic passivation layers, ona number of different surfaces. Further information and examples ofselective deposition of metal oxide and other layers of interest areprovided below.

Alternatively, the layer of interest X is a metal layer. U.S. Pat. No.8,956,971, issued Feb. 17, 2015 and U.S. Pat. No. 9,112,003, issued Aug.18, 2015, the entire disclosures of which are incorporated herein byreference for all purposes, teach processes for selective deposition ofmetallic materials on metallic surfaces, relative to other materialsurfaces, including organic surfaces.

FIG. 2E shows the substrate of FIG. 2D after removal of the passivationlayer from the first surface, leaving a selectively formed dielectric onmetal or metal on metal. The passivation layer can be removed asdescribed above with respect to the first embodiment, such as by O₃etching.

FIGS. 3A-3B illustrate a third embodiment for selective passivation of afirst surface relative to a second surface, followed by selectivedeposition on the second surface relative to the passivated firstsurface. In the illustrated embodiment, the process of FIGS. 2A-2D isfirst conducted.

FIG. 3A shows the substrate of FIG. 2D after a further selectivedeposition. In the event the layer of interest X is a metallic material,the further selective deposition can form a dielectric material as asecond layer of interest Y over the first layer of interest, selectivelyrelative to the organic passivation layer. As noted above with respectto the first and second embodiments, and described in theabove-incorporated provisional patent application No. 62/332,396, filedMay 5, 2016, metal oxides can be selectively deposited using vapordeposition techniques and hydrophobic precursors to aid selectivityrelative to organic passivation layers, on a number of differentsurfaces. Further information and examples of selective deposition ofmetal oxide and other layers of interest are provided below.

FIG. 3B shows the substrate of FIG. 3A after removal of the passivationlayer from the first surface, leaving a selectively formed dielectric onmetal. The passivation layer can be removed as described above withrespect to the first embodiment, such as by O₃ etching.

The second and third embodiments, like the first embodiment, can involveadditional treatments, such as heat or chemical treatment, conductedprior to, after or between the foregoing processes.

Selective Deposition of Passivation Layer

As disclosed in the incorporated U.S. patent application Ser. No.15/170,769, filed Jun. 1, 2016, vapor phase deposition techniques can beapplied to organic passivation layers and polymers such as polyimidelayers, polyamide layers, polyuria layers, polyurethane layers,polythiophene layers, and more. CVD of polymer layers can producegreater thickness control, mechanical flexibility, conformal coverage,and biocompatibility as compared to the application of liquid precursor.Sequential deposition processing of polymers can produce high growthrates in small research scale reactors. Similar to CVD, sequentialdeposition processes can produce greater thickness control, mechanicalflexibility, and conformality. The terms “sequential deposition” and“cyclical deposition” are employed herein to apply to processes in whichthe substrate is alternately or sequentially exposed to differentprecursors, regardless of whether the reaction mechanisms resemble ALD,CVD, MLD or hybrids thereof.

Referring to FIG. 4A and in some embodiments, a substrate comprising afirst surface and a second surface is provided at block 11. The firstand second surfaces may have different material properties as discussedherein. In some embodiments, the first surface may be a conductivesurface, for example a metal or metallic surface, and the second surfacemay be a dielectric surface (see, e.g., FIGS. 1A-1D). In someembodiments, the first surface may be a dielectric surface and thesecond surface may be a second, different dielectric surface. In someembodiments, the first surface may be a dielectric surface, for examplea silicon oxide-based material, and the second surface may be apassivation blocking material such as an SAM (see, e.g., FIGS. 2A-3B).

In some embodiments, the first precursor may be vaporized at a firsttemperature to form the first vapor phase precursor. In someembodiments, the first precursor vapor is transported to the substratethrough a gas line at a second temperature. In some embodiments, thesecond transportation temperature is higher than the first vaporizationtemperature. In some embodiments, the substrate is contacted with afirst vapor phase precursor, or reactant, at block 12 for a firstexposure period. In some embodiments, the substrate may be contactedwith the first vapor phase precursor at a third temperature that ishigher than the first temperature.

In some embodiments, the first precursor exposure period is from about0.01 seconds to about 60 seconds, about 0.05 seconds to about 30seconds, about 0.1 seconds to about 10 seconds or about 0.2 seconds toabout 5 seconds. The optimum exposure period can be readily determinedby the skilled artisan based on the particular circumstances. In someembodiments where batch reactors may be used, exposure periods ofgreater than 60 seconds may be employed.

In some embodiments, the substrate is contacted with a second vaporphase precursor, or reactant, at block 13 for a second exposure period.In some embodiments, the second precursor may be vaporized at a fourthtemperature to form the second vapor phase precursor. In someembodiments, the second reactant vapor is transported to the substratethrough a gas line at a second temperature. In some embodiments, thefifth transportation temperature is higher than the first vaporizationtemperature. In some embodiments, the substrate may be contacted withthe second vapor phase precursor at a sixth temperature that is higherthan the fourth temperature. In some embodiments, the sixth temperaturemay be substantially the same as the third temperature at which thefirst vapor phase precursor contacts the substrate.

In some embodiments, the second precursor exposure period is from about0.01 seconds to about 60 seconds, about 0.05 seconds to about 30seconds, about 0.1 seconds to about 10 seconds or about 0.2 seconds toabout 5 seconds. The optimum exposure period can be readily determinedby the skilled artisan based on the particular circumstances. In someembodiments, where batch reactors may be used, exposure periods ofgreater than 60 seconds may be employed.

In block 14 an organic layer is selectively deposited on the firstsurface relative to the second surface. The skilled artisan willappreciate that selective deposition of an organic layer is the resultof the above-described contacting actions, 12-13, rather than a separateaction. In some embodiments, the above-described contacting actions,blocks 12-13, may be considered a deposition cycle. Such a selectivedeposition cycle can be repeated until a layer of sufficient thicknessis left on the substrate (block 15) and the deposition is ended (block16). The selective deposition cycle can include additional acts, neednot be in the same sequence nor identically performed in eachrepetition, and can be readily extended to more complex vapor depositiontechniques. For example, a selective deposition cycle can includeadditional reactant supply processes, such as the supply and removal(relative to the substrate) of additional reactants in each cycle or inselected cycles. Though not shown, the process may additionally comprisetreating the deposited layer to form a polymer (for example, UVtreatment, annealing, etc.). The selectively formed organic layer canserve as a passivation layer to inhibit deposition thereover andincrease selectivity in a subsequent selective deposition of a layer ofinterest, as noted above

Referring to FIG. 4B, the vapor deposition process of FIG. 4A may insome embodiments comprise an atomic layer deposition process. Asubstrate comprising a first surface and a second surface is provided atblock 21. The first and second surfaces may have different materialproperties. In some embodiments, the first surface may be a conductivesurface, for example a metal or metallic surface, and the second surfacemay be a dielectric surface (see, e.g., FIGS. 1A-1D). In someembodiments, the first surface may be a dielectric surface and thesecond surface may be a second, different dielectric surface. In someembodiments, the first surface may be a dielectric surface, for examplea silicon oxide-based material, and the second surface may be apassivation blocking material such as an SAM (see, e.g., FIGS. 2A-3B).

In some embodiments a sequential deposition method for selective vapordeposition of an organic passivation layer comprises vaporizing a firstorganic precursor is at a first temperature to form a first precursorvapor at block 22. In some embodiments, the first precursor vapor istransported to the substrate through a gas line at a second temperature.In some embodiments the second transportation temperature is higher thanthe first vaporization temperature. In some embodiments, the substrateis contacted with the vapor phase first precursor for a first exposureperiod at block 23. In some embodiments, the first precursor, or speciesthereof, chemically adsorbs on the substrate in a self-saturating orself-limiting fashion. The gas line can be any conduit that transportsthe first precursor vapor from the source to the substrate. In someembodiments, the substrate may be exposed to the first precursor vaporat a third temperature that is higher than the first temperature.

In some embodiments the first precursor exposure period is from about0.01 seconds to about 60 seconds, about 0.05 seconds to about 30seconds, about 0.1 seconds to about 10 seconds or about 0.2 seconds toabout 5 seconds. The optimum exposure period can be readily determinedby the skilled artisan based on the particular circumstances. In someembodiments, where batch reactors may be used, exposure periods ofgreater than 60 seconds may be employed.

Excess of the first precursor vapor (and any volatile reactionby-products) may then be removed from contact with the substrate atblock 24. Such removal can be accomplished by, for example, purging,pump down, moving the substrate away from a chamber or zone in which itis exposed to the first reactant, or combinations thereof. In someembodiments, a first precursor removal period, for example a purgeperiod, is from about 0.01 seconds to about 60 seconds, about 0.05seconds to about 30 seconds, about 0.1 seconds to about 10 seconds orabout 0.2 seconds to about 5 seconds. The optimum removal period can bereadily determined by the skilled artisan based on the particularcircumstances. In some embodiments, where batch reactors may be used,removal periods of greater than 60 seconds may be employed.

In some embodiments, the second precursor may be vaporized at a fourthtemperature to form the second vapor phase precursor at block 25. Insome embodiments, the second reactant vapor is transported to thesubstrate through a gas line at a second temperature. In someembodiments, the fifth transportation temperature is higher than thefirst vaporization temperature. In some embodiments, the substrate maybe contacted with the second vapor phase precursor at a sixthtemperature that is higher than the fourth temperature. In someembodiments, the sixth temperature may be substantially the same as thethird temperature at which the first vapor phase precursor contacts thesubstrate. In some embodiments, the substrate may be exposed to a secondprecursor vapor for a second exposure period at block 26. In someembodiments, the second reactant may react with the adsorbed species ofthe first reactant on the substrate.

In some embodiments, the first precursor exposure period is from about0.01 seconds to about 60 seconds, about 0.05 seconds to about 30seconds, about 0.1 seconds to about 10 seconds or about 0.2 seconds toabout 5 seconds. The optimum exposure period can be readily determinedby the skilled artisan based on the particular circumstances. In someembodiments, where batch reactors may be used, exposure periods ofgreater than 60 seconds may be employed.

In some embodiments, excess of the second precursor vapor (and anyvolatile reaction by-product) is removed from contact with the substrateat block 27, such that the first reactant vapor and the second reactantvapor do not mix. In some embodiments, the vapor deposition process ofthe organic layer does not employ plasma and/or radicals, and can beconsidered a thermal vapor deposition process. In some embodiments, asecond precursor removal period, for example a purge period, is fromabout 0.01 seconds to about 60 seconds, about 0.05 seconds to about 30seconds, about 0.1 seconds to about 10 seconds or about 0.2 seconds toabout 5 seconds. The optimum removal period can be readily determined bythe skilled artisan based on the particular circumstances. In someembodiments, where batch reactors may be used, removal periods ofgreater than 60 seconds may be employed.

In block 28 an organic layer is selectively deposited on the firstsurface relative to the second surface. The skilled artisan willappreciate that selective deposition of an organic layer is the resultof the above-described contacting actions rather than a separate action.In some embodiments, the above-described contacting and removing (and/orhalting supply) actions, blocks 23-27, may be considered a depositioncycle. In some embodiments, a deposition cycle may be repeated until anorganic layer of a desired thickness is selectively deposited. Such aselective deposition cycle can be repeated (block 29) until a layer ofsufficient thickness is left on the substrate and the deposition isended (block 30). The selective deposition cycle can include additionalacts, need not be in the same sequence nor identically performed in eachrepetition, and can be readily extended to more complex vapor depositiontechniques. For example, a selective deposition cycle can includeadditional reactant supply processes, such as the supply and removal ofadditional reactants in each cycle or in selected cycles. Though notshown, the process may additionally comprise treating the depositedlayer to form a polymer (for example, UV treatment, annealing, etc.).

Various reactants can be used for the above described processes. Forexample, in some embodiments, the first precursor or reactant is anorganic reactant such as a diamine, e.g., 1,6-diaminohexane (DAH), orany other monomer with two reactive groups. In some embodiments, thesecond reactant or precursor is also an organic reactant capable ofreacting with adsorbed species of the first reactant under thedeposition conditions. For example, the second reactant can be ananhydride, such as furan-2,5-dione (maleic acid anhydride). Theanhydride can comprise a dianhydride, e.g., pyromellitic dianhydride(PMDA), or any other monomer with two reactive groups which will reactwith the first reactant.

In some embodiments the substrate is contacted with the first precursorprior to being contacted with the second precursor. Thus, in someembodiments the substrate is contacted with an amine, such as a diamine,for example 1,6-diaminohexane (DAH) prior to being contacted withanother precursor. However, in some embodiments the substrate may becontacted with the second precursor prior to being contacted with thefirst precursor. Thus, in some embodiments the substrate is contactedwith an anhydride, such as furan-2,5-dione (maleic acid anhydride), ormore particularly a dianhydride, e.g., pyromellitic dianhydride (PMDA)prior to being contacted with another precursor.

In some embodiments, different reactants can be used to tune the layerproperties. For example, a polyimide layer could be deposited using4,4′-oxydianiline or 1,4-diaminobenzene instead of 1,6-diaminohexane toget a more rigid structure with more aromaticity and increased dry etchresistance.

In some embodiments, the reactants do not contain metal atoms. In someembodiments, the reactants do not contain semimetal atoms. In someembodiments, one of the reactants comprises metal or semimetal atoms. Insome embodiments, the reactants contain carbon and hydrogen and one ormore of the following elements: N, O, S, P or a halide, such as Cl or F.In some embodiments, the first reactant may comprise, for example,adipoyl chloride (AC).

Deposition conditions can differ depending upon the selected reactantsand can be optimized upon selection. In some embodiments, the reactiontemperature can be selected from the range of about 80° C. to about 250°C. In some embodiments, the reaction chamber pressure may be from about1 mTorr to about 1000 Torr. In some embodiments, for example where theselectively deposited organic layer comprises polyamide, the reactiontemperature can be selected from a range of about 80° C. to about 150°C. In some embodiments where the selectively deposited organic layercomprises polyamide, the reaction temperature may be greater than about80° C., 90° C., 100° C., 110° C., 120° C., 130° C., 140° C., or 150° C.In some embodiments where the selectively deposited organic layercomprises polyimide, the reaction temperature may be greater than about160° C., 180° C., 190° C., 200° C., or 210° C.

For example, for sequential deposition of polyimide using PMDA and DAHin a single wafer deposition tool, substrate temperatures can beselected from the range of about 150° C. to about 250° C., or from about170° C. to about 210° C., and pressures can be selected from the rangeof about 1 mTorr to about 760 Torr, more particularly between about 100mTorr to about 100 Torr.

In some embodiments reactants for use in the selective depositionprocesses described herein may have the general formula:

R¹(NH₂)₂  (1)

wherein R¹ may be an aliphatic carbon chain comprising 1-5 carbon atoms,2-5 carbon atoms, 2-4 carbon atoms, 5 or fewer carbon atoms, 4 or fewercarbon atoms, 3 or fewer carbon atoms, or 2 carbon atoms. In someembodiments, the bonds between carbon atoms in the reactant or precursormay be single bonds, double bonds, triple bonds, or some combinationthereof. Thus, in some embodiments a reactant may comprise two aminogroups. In some embodiments, the amino groups of a reactant may occupyone or both terminal positions on an aliphatic carbon chain. However, insome embodiments the amino groups of a reactant may not occupy eitherterminal position on an aliphatic carbon chain. In some embodiments, areactant may comprise a diamine. In some embodiments, a reactant maycomprise an organic precursor selected from the group of1,2-diaminoethane (1), 1,3-diaminopropane (1), 1,4-diaminobutane (1),1,5-diaminopentane (1), 1,2-diaminopropane (1), 2,3-butanediamine,2,2-dimethyl-1,3-propanediamine (1).

In some embodiments, reactants for use in the selective depositionprocesses described herein may have the general formula:

R²(COCl)₂  (2)

wherein R² may be an aliphatic carbon chain comprising 1-3 carbon atoms,2-3 carbon atoms, or 3 or fewer carbon atoms. In some embodiments, thebonds between carbon atoms in the reactant or precursor may be singlebonds, double bonds, triple bonds, or some combination thereof. In someembodiments, a reactant may comprise a chloride. In some embodiments, areactant may comprise a diacyl chloride. In some embodiments, a reactantmay comprise an organic precursor selected from the group of oxalylchloride (I), malonyl chloride, and fumaryl chloride.

In some embodiments, a reactant comprises an organic precursor selectedfrom the group of 1,4-diisocyanatobutane or 1,4-diisocyanatobenzene. Insome embodiments, a reactant comprises an organic precursor selectedfrom the group of terephthaloyl dichloride, alkyldioyl dichlorides, suchas hexanedioyl dichloride, octanedioyl dichloride, nonanedioyldichloride, decanedioyl dichloride, or terephthaloyl dichloride. In someembodiments, a reactant comprises an organic precursor selected from thegroup of 1,4-diisothiocyanatobenzene or terephthalaldehyde. In someembodiments, a reactant being vaporized can be also a diamine, such as1,4-diaminobenzene, decane-1,10-diamine, 4-nitrobenzene-1,3-diamine,4,4′-oxydianiline, or ethylene diamine. In some embodiments, a reactantcan be a terephthalic acid bis(2-hydroxyethyl) ester. In someembodiments, a reactant can be a carboxylic acid, for example alkyl-,alkenyl-, alkadienyl-dicarboxylic or tricarboxylic acid, such asethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acidor propane-1,2,3-tricarboxylic acid. In some embodiments, a reactant canbe an aromatic carboxylic or dicarboxylic acid, such as benzoic acid,benzene-1,2-dicarboxylic acid, benzene-1,4-dicarboxylic acid orbenzene-1,3-dicarboxylic acid. In some embodiments, a reactant maycomprise one or more OH-groups bonded to a hydrocarbon. In someembodiments, a reactant can be selected from the group of diols, triols,aminophenols such as 4-aminophenol, benzene-1,4-diol orbenzene-1,3,5-triol. In some embodiments, a reactant can be8-quinolinol. In some embodiments, the reactant can comprisealkenylchlorosilanes, like alkenyltrichlorosilanes, such as7-octenyltrichlorosilane.

In some embodiments, a reactant may have a vapor pressure greater thanabout 0.5 Torr, 0.1 Torr, 0.2 Torr, 0.5 Torr, 1 Torr or greater at atemperature of about 20° C. or room temperature. In some embodiments, areactant may have a boiling point less than about 400° C., less than300° C., less than about 250° C., less than about 200° C., less thanabout 175° C., less than about 150° C., or less than about 100° C.

Example 1: Selective Deposition of Passivation Layer

Sample polyimide thin layers were deposited on a number of substratesaccording to selective deposition processes described herein. 200 mmsilicon wafers having tungsten (W) features alternated with siliconoxide surfaces were used as substrates. The width of the tungstenfeatures was 250 nm with a pitch of approximately 600 nm. The polyimidedeposition processes were performed in a Pulsar 3000® cross-flow ALDreactor connected with PRI cluster tool.

A first batch of sample polyimide layers were deposited according to theprocesses described herein using DAH as a first vapor phase reactant andPMDA as a second vapor phase reactant. The DAH first reactant wassupplied at 45° C. by an N₂ carrier gas having a flow rate of 450 sccm.The DAH pulse time was 5 seconds and the DAH pure time was 4 seconds.The PMDA second reactant was supplied to the reaction chamber at 180° C.by an N₂ carrier gas having a flow rate of 450 sccm. The PMDA pulse timewas 11 seconds and the PMDA purge time was 4 seconds. The reaction orsubstrate temperature was 160° C. Polyimide layers were deposited usingbetween 25 and 100 deposition cycles.

A second batch of sample polyimide layers were deposited according tothe processes described herein using substantially similar conditions asthe first batch, but having a reaction temperature of 190° C. Polyimidelayers were deposited using between 250 and 1000 deposition cycles.

The thicknesses of the polyimide layer samples were measured usingscanning transmission electron microscopy. The first batch of polyimidelayers were found to have thicknesses between 5 nm for a process having25 deposition cycles and 40 nm for a process having 100 depositioncycles with a growth rate of about 4-6 Å/cycle. The amount of polyimidedeposited on the W surfaces of the substrate was substantially the sameas the amount of polyimide deposited on the silicon oxide surface.Therefore, the deposition was not selective at a reaction temperature of160° C. for this recipe.

The second bath of polyimide layers were found to have thicknessesranging from about 7 nm for a process having 250 cycles to about 28 nmfor a process having 1000 cycles on the W surfaces. Polyimide layerthicknesses on the silicon oxide surfaces ranged from about 4 nm for aprocess having 250 cycles to about 6 nm for a process having 1000cycles. Therefore, the polyimide deposition was selective at a reactiontemperature of 190° C. The growth rate on the W surfaces was about 0.2-1Å/cycle.

Example 2: Selective Deposition of Passivation Layer

A sample polyimide layer was selectively deposited on a 200 mm siliconwafer having patterned tungsten (W) features alternated with siliconoxide surfaces according to the processes described herein using DAH asa first vapor phase reactant and PMDA as a second vapor phase reactant.The DAH first reactant was supplied at 45° C. by an N₂ carrier gashaving a flow rate of 450 sccm. The DAH pulse time was 5 seconds and theDAH pure time was 4 seconds. The PMDA second reactant was supplied tothe reaction chamber at 180° C. by an N₂ carrier gas having a flow rateof 450 sccm. The PMDA pulse time was 11 seconds and the PMDA purge timewas 4 seconds. The reaction temperature was 190° C. The polyimide samplelayer was deposited using 1000 deposition cycles. The polyimide wasdeposited on the W surface, with a layer thickness of about 30 nm. Asubstantially lesser amount of polyimide was deposited on the siliconoxide surface, about 4 nm.

The sample polyimide layer was then etched with H₂ plasma generatedusing 100 W at a temperature of 300° C. for 40 seconds. The flow rate ofthe H₂ gas was 100 sccm. Polyimide was completely removed from thesilicon oxide surface while a polyimide layer having a thickness ofabout 9 nm was left on the W surface.

Selective Deposition of Layers of Interest Relative to Organic Surfaces

As disclosed in the incorporated U.S. provisional patent application No.62/332,396, filed May 5, 2016, selective deposition of metallicmaterials, and particularly metal oxides, relative to organic materialssuch as the passivation layers disclosed herein, can be facilitated byemploying hydrophobic reactants. After selectively forming a passivationlayer on the first surface, in some embodiments a metal oxide isselectively deposited on the second surface by contacting the substratealternately and sequentially with a first hydrophobic reactantcomprising a metal of the metal oxide and a second reactant comprisingoxygen. In some embodiments, the second reactant is water. In someembodiments the substrate is contacted sequentially with the first andsecond reactants, similar to the sequence of FIG. 4A, except that anon-organic layer is selectively deposited on or over the second surface(see, e.g., FIGS. 1A-3B).

The hydrophobic reactant comprises one or more hydrophobic ligands. Insome embodiments, the hydrophobic reactant comprises two to fourhydrophobic ligands. In the case of hydrophobic reactants comprising ametal with a valence/oxidation state of n, in some embodiments, thehydrophobic precursor comprises n-1 or n-2 hydrophobic ligands.

In some embodiments, at least one hydrophobic ligand comprises only Cand H. In some embodiments, at least one hydrophobic ligand comprises C,H and Si or Ge, but no additional elements.

In some embodiments, a hydrocarbon ligand comprises one or more of thefollowing:

-   -   C1-C10 hydrocarbon (single, double or triple bonded)        -   Alkyls            -   C1-C5 alkyls                -   Me, Et, Pr, ^(i)Pr, Bu, ^(t)Bu        -   Alkenyls            -   C1-C6 alkenyls        -   Cyclic hydrocarbons            -   C3-C8                -   Cyclopentadienyl                -   Cycloheptadienyl                -   Cycloheptatrienyl                -   Cyclohexyl                -   Derivatives of those        -   Aromatic            -   C6 aromatic ring and derivatives of those

In some embodiments, the hydrophobic reactant comprises no hydrophilicligands. However, in some embodiments the hydrophobic reactant maycomprise one or two hydrophilic ligands. In some embodiments, ahydrophilic ligand comprises nitrogen, oxygen and/or a halogen group.

In some embodiments, a hydrophilic ligand is an alkylamine (—NR₂, whereeach R can be alkyl, hydrogen). In some embodiments, the hydrophilicligand can be —NMe₂, —NEtMe, or —NEt₂.

In some embodiments, a hydrophilic ligand is an alkoxide, for example—OMe, —OEt, —O^(i)Pr, —O^(t)Bu.

In some embodiments, a hydrophilic ligand comprises a halide, such as achloride, fluoride or other halide.

In some embodiments, the hydrophobic precursor comprises the formula:

L_(n)MX_(y), in which

-   -   In some embodiments n is from 1-6;        -   In some embodiments n is from 1-4 or 3-4.    -   In some embodiments y is from 0-2;        -   In some embodiments y is from 0-1.    -   L is a hydrophobic ligand;        -   In some embodiments L is Cp or a C1-C4 alkyl ligand.    -   X is hydrophilic ligand;        -   In some embodiments X is an alkylamine, alkoxide or halide            ligand.    -   M is metal (including group 13 elements, B, Ga);        -   In some embodiments M has an oxidation state of +I up to            +VI.            -   In some embodiments M has an oxidation state of +IV to                +V.        -   In some embodiments M can be a transition metal.            -   In some embodiments M is Ti, Ta, Nb, W, Mo, Hf, Zr, V,                or Cr.                -   In some embodiments M is Hf, Zr, Ta or Nb.                -    In some embodiments M is Zr.            -   In some embodiments M is Co, Fe, Ni, Cu, or Zn.            -   In some embodiments the metal is not W or Mo.        -   In some embodiments M can be a rare earth metal.            -   In some embodiments M is La, Ce, or Y.        -   In some embodiments M can be a metal from groups of 2-13.            -   In some embodiments M is Ba, Sr, Mg, Ca, or Sc.        -   In some embodiments M is not a noble metal.

More generally, in some embodiments, the selective ALD process employs ametal precursor. In some embodiments, the metal of the metal precursormay be selected from the group comprising Al, Ti, Ta, Nb, W, Mo, Hf, Zr,V, Cr, Co, Fe, Ni, Cu, Zn, La, Ce, Y, Ba, Sr, Mg, Ca, or Sc, or mixturesthereof. In some embodiments, the metal may be Al.

In some embodiments, the hydrophobic reactant isBis(methylcyclopentadienyl) methoxymethyl Zirconium(IV)((CpMe)₂-Zr—(OMe)Me).

In some embodiments, the hydrophobic reactant isbis(methylcyclopentadienyl) methoxymethyl Hafnium(IV)((CpMe)₂-Hf—(OMe)Me).

In other embodiments, the selective ALD process employs an Al precursor.Examples of Al precursors include trimethyl aluminum (TMA), aluminumtrichloride (AlCl₃) and triethyl aluminum (TEA).

In some embodiments, the second reactant contributes one or moreelements to the material that is selectively deposited. For example, thesecond reactant can be an oxygen precursor used to deposit a metal oxideor a nitrogen precursor used to deposit a metal nitride.

In some embodiments, the second reactant comprises an oxygen precursor.

In some embodiments, the second reactant comprises H₂O.

In some embodiments, the second reactant comprises O₃.

In some embodiments, the second reactant comprises H₂O₂.

In some embodiments, the second reactant comprises oxygen plasma, ions,radicals, atomic O or excited species of oxygen.

In some embodiments, the second reactant comprises a nitrogen precursor.

In some embodiments, the second reactant comprises NH₃.

In some embodiments, the second reactant comprises N₂H₄.

In some embodiments, the second reactant comprises nitrogen containingplasma, ions, radicals, atomic N or excited species comprising N. Insome embodiments, the nitrogen reactant can comprise a mixture withcorresponding hydrogen species.

In some embodiments, other reactants can be utilize that contributeelements other than N or O to the deposited material. These reactantsmay be used in addition to a N or O second reactant, or may themselvesserve as a second reactant. For example, in some embodiments a sulfurreactant may be used to deposit a sulphide, a carbon reactant may beused to deposit carbon or a silicon reactant may be used to deposit asilicide.

In some embodiments, a second (or additional) reactant may be used thataid in depositing a metal or metallic film, such as an elemental metalfilm. For example, in some embodiments a hydrogen reactant may be used.

Alternatively, as described with respect to FIG. 2D, a metallicconductive film of interest can be selectively deposited on the secondsurface, particularly a metallic surface, relative to the organicpassivation layer. For example, U.S. Pat. No. 8,956,971, issued Feb. 17,2015 and U.S. Pat. No. 9,112,003, issued Aug. 18, 2015, the entiredisclosures of which are incorporated herein by reference for allpurposes, teach processes for selective deposition of metallic materialson metallic surfaces relative to non-metallic surfaces, includingorganic materials. As also noted above with respect to FIG. 3A, afurther dielectric layer, particularly a metal oxide material, can beselectively formed over the selectively formed metallic material layerprior to removal of the organic passivation layer.

Examples: Selective Metal Oxide Deposition

FIGS. 5-7 illustrate that metal oxides can be deposited selectively oninorganic dielectrics relative to organic passivation layers. Inexperiments, the inorganic passivation layer comprises a depositedpolymer, particularly polyimide, which can be selectively formed asdescribed above.

Deposition of ZrO₂ by ALD on various substrates and under variousreaction conditions was carried out in a Pulsar® 2000 reactor.Bis(methylcyclopentadienyl) methoxymethyl Zirconium(IV)((CpMe)₂-Zr—(OMe)Me) and H₂O were used in an ALD process for depositinga ZrO₂ film. Deposition of ZrO₂ was not observed on substratescomprising a surface with a SAM layer (Trichloro(octadecyl)silane) or apolyimide surface. See FIGS. 4-5.

In FIG. 5 it can be seen shown that the ZrO₂ grows on native oxide(silicon oxide) but not significantly on polyimide. Even after almost 25nm of ZrO₂ was deposited on the native oxide (SiO₂) surface there was nosignificant ZrO₂ on the polyimide surface, even though on the surface ofpolyimide there are hydrophilic surface groups present like C—NH₂.

Polyimide samples after 100 to 760 ZrO₂ cycles on native oxide,polyimide surfaces, as well as on H-plasma damaged polyimide surface andO-plasma damaged polyimide surface, were analyzed by XPS.Bis(methylcyclopentadienyl) methoxymethyl Zirconium(IV)((CpMe)₂-Zr—(OMe)Me) was alternated with water (H₂O) in an ALD sequenceat 300° C. Only a very small amount of Zr or ZrO₂ was detected onpolyimide surfaces even after 760 cycles. The H plasma damaged surfacealso inhibited ZrO₂ growth, but the O-plasma damaged the polyimidesufficiently to allow significant deposition, albeit less than thedeposition on native oxide.

HfO₂ deposited in an ALD sequence from Bis(methylcyclopentadienyl)methoxymethyl Hafnium(IV) ((CpMe)₂-Hf—(OMe)Me) alternated with water(H₂O) similarly exhibits high selectivity on native oxide relative topolyimides deposited with two different types of cyclical depositionsequences (PMDA-LAST and DAH-LAST). No HfO₂ was detected on thepolyimide surfaces with either cyclical deposition sequences even after750 cycles of HfO₂ deposition, while the native oxide showed measurabledeposition even after fewer cycles.

XPS data also detected negligible Hf on polyimide after 150-750 ALDcycles of Bis(methylcyclopentadienyl) methoxymethyl Hafnium(IV)((CpMe)₂-Hf—(OMe)Me) alternated with water (H₂O).

FIG. 6 shows that titanium oxide (TiO₂) films readily grow at very lowtemperatures on native oxide, and in fact grow at higher rates at lowtemperatures compared to high temperatures. The films were depositedusing an ALD sequence alternating TiCl₄ with water.

FIG. 7, in contrast, shows that the same ALD sequence for depositingTiO₂ on polyimide surfaces, while exhibiting a similar tendency tohigher growth rates at lower temperatures, demonstrated significantlylower rates of deposition at any given temperature, such that theprocess is relatively selective on native oxide relative to polyimide,even at lower temperatures. Moreover, at temperatures of 250° C. orabove, negligible deposition was found on polyimide, such that thedeposition appears to be fully selective.

In summary, data from experiments indicated high degrees of selectivityfor ALD of metal oxides on native oxide relative to polyimide under avariety of temperature conditions for:

-   -   ZrO₂ deposited from Bis(methylcyclopentadienyl) methoxymethyl        Zirconium(IV) alternated with water (H₂O), at temperatures of        275-325° C., selectivity relative to polyimide was maintained        for more than 25 nm over native oxide    -   TiO₂ deposited from TiCl₄ alternated with water, selectivity        relative to polyimide was maintained for about 100 cycles at        250° C., and for much greater than 100 cycles at 300° C.    -   HfO₂ deposited from deposited from Bis(methylcyclopentadienyl)        methoxymethyl Hafnium(IV) alternated with water (H₂O), at        temperatures of 280° C., selectivity relative to polyimide was        maintained for more than 25 nm over native oxide

The skilled artisan will appreciate that the foregoing representnon-limiting conditions under which selectivity was demonstrated, andthat selectivity may be maintained under a variety of other conditionsnot tested. However, aluminum oxide deposited by alternating TMA andwater at temperatures from 50-230° C., and ZrO₂ from alternatingBis(methylcyclopentadienyl) methoxymethyl Zirconium(IV) alternated withozone (O₃) did not demonstrate good selectivity on native oxide relativeto polyimide.

Passivation Blocking Layer

As noted above, a self-assembled monolayer (SAM) can serve to inhibitdeposition of an organic passivation layer, thus facilitating selectivedeposition of the organic passivation layer on other surfaces. The term“blocking” is thus merely a label and need not imply 100% deactivationof the organic passivation layer deposition. As noted elsewhere herein,even imperfect selectivity can suffice to obtain a fully selectivestructure after an etch back process.

In one embodiment, a passivation blocking layer is formed on the secondsurface to inhibit deposition of for comprises an SAM containing sulfur.In one embodiment, the second surface is a metallic surface. In oneembodiment, the metallic surface is pretreated with acid treatmentsprior to SAM formation.

Experiments were conducted on vapor phase deposition of asulfur-containing SAM in a small research and development tool (F-120®reactor). Substrates with exposed metallic surfaces, comprisingelectrochemically-deposited copper in the experiments, were exposed toliquid acid pretreatment of 30 seconds, using 3.5% aqueous formic acidand 3.5% aqueous HCl in various experiments; or gaps phase formic acidin 10 ten-second pulses. A sulfur-containing monomer, namely1-dodecananethiol (CH₃(CH₂)₁₁SH), which can be referred to as a ThiolSAM precursor or monomer, was provided to the substrate at differenttemperatures ranging from 75° C. to 150° C. for various exposure times.The exposures were conducted by way of alternating vapor phasecontacting phases and removal phases of 5 s each. For example, the 15minute exposure was provided in the form of 180 five-second pulsesalternated with five-second purges.

FIG. 8 shows the effect of time of exposure at 75° C. The measured watercontact angles were greater than 100° after exposure to the vapor phasesulfur-containing monomer of 15 minutes or greater, indicating formationof an effective SAM layer. On smooth copper surfaces, water contactangles on SAMs with —CH₃ surface groups are about 110°, whereas on roughcopper surfaces the water contact angle is even higher.

FTIR analysis of a sample with sulfur-containing SAM over copper showsthat the SAM was formed by vapor deposition as described above, with themonomer source vessel heated to 55° C., and the deposition temperaturesranging from 75-150° C. The FTIR analysis indicated the presence of —CH₂surface groups but not S—C surface groups, despite the fact that XPSanalysis shows 5-6 atomic % of sulfur on the copper surface.Accordingly, the monomers coordinate the sulfur-containing groups withcopper and present hydrophobic hydrocarbon surface groups, as indicatedby high water contact angles.

FIGS. 9-10 demonstrate that high water contact angles result on the SAMsformed with both HCl liquid pretreatment (112°, FIG. 9) and HCOOH gasphase pretreatment (117°, FIG. 10).

Selective Passivation Layer Deposition Relative to Passivation BlockingLayer

FIGS. 11-15 illustrate that a passivation blocking layer can facilitateselective formation of an organic passivation layer on dielectricmaterial relative to the passivation blocking layer.

FIG. 11 shows the results of experiments depositing polymer layers,particularly polyimide employing the processes described above, oncopper and sulfur-containing SAM surfaces. The polyimide layer wasdeposited at 160° C. for 20 cycles, which process deposits about 4.4 nmof polyimide over native oxide. As shown, water contact angle hardlychanged when the passivation blocking SAM was exposed to the polyimidedeposition process, whereas the water contact angle increased when abare copper surface was exposed to the polyimide deposition process.

FIG. 12 shows the results of XPS analysis of the SAM surface, the SAMsurface exposed to the polyimide deposition process, a bare coppersurface exposed to the polyimide deposition process, and a native oxidesurface exposed to the polyimide process. The amount of sulfur detectedon the SAM surface was unchanged after exposure to the polyimidedeposition process. The SAM surface had no detectable amount ofnitrogen, and very little nitrogen (0.6 atomic %) after exposure to thepolyimide deposition process. In contrast, both the bare copper andnative oxide surfaces showed significant nitrogen content (around 10atomic %). Both FIGS. 11 and 12 demonstrate that the sulfur-containingSAM inhibits deposition of the organic passivation layer thereover.

FIG. 13 shows XPS analysis of surfaces after exposure of varioussurfaces to various cycle numbers of an organic passivation layerdeposition as described herein. In the experiments for FIG. 13, variouscycles of polyimide were conducted at 190° C. The passivation blockinglayer was a sulfur-containing SAM deposited from gas phase monomer in anF-120® reactor. The XPS analysis shows that the SAM inhibits polyimidegrowth thereover, whereas polyimide grows on bare copper and nativeoxide. Additionally, the water contact angle of the SAM was 120° priorto exposure to the polyimide deposition process, 100° after exposure to100 cycles of the polyimide deposition process, and 95° after exposureto 250 cycles of the polyimide deposition process.

FIGS. 14 and 15 show that the sulfur-containing SAM can be selectivelyformed on metallic surfaces relative to dielectric surfaces. Inparticular, after exposure of copper to the sulfur-containing vaporphase monomer, the water contact angle on the surface was around 117°.In contrast, the water contact angle remained low (around 26°) andunchanged over a native oxide surface.

Deposition Equipment

Examples of suitable reactors that may be used in the selectivedeposition processes described herein include commercially available ALDequipment such as the F-120® reactor, Pulsar® reactor, such as a Pulsar3000® or Pulsar 2000®, and Advance® 400 Series reactor, available fromASM America, Inc. of Phoenix, Ariz. and ASM Europe B.V., Almere,Netherlands. In addition to these ALD reactors, many other kinds ofreactors capable growth of organic passivation layers, including CVDreactors, VDP reactors, and MLD reactors, can be employed.

The selective dielectric on dielectric deposition described herein withrespect to FIGS. 1A-1D could be performed in up to five processes. (1)pretreatment, (2) selective organic passivation layer deposition on thefirst surface; (3) partial etch back, also referred to as a “clean-up”etch, of any organic material from over the second surface, (4)selective dielectric deposition on the second surface; and (5) removalof the organic passivation layer from over the first surface.

In one embodiment, tools for the sequence can be minimized by combiningthe (2) selective organic passivation layer deposition and the (3)partial etch-back in one chamber, and using a clustered chamber toconduct the (4) selective dielectric deposition on the second surface.The pretreatment can either be performed on another platform (e.g., wetbench) or omitted through tuning of certain recipes. The organicpassivation layer removal may be performed in a separate ashing tool,such as those often used for removal of photoresist and other organicmaterials, or in the deposition chamber using the same or a similarchemistry used for the partial etch back of organic material. Thus, thedeposition stages and intervening etch back can be performed in platformthat comprises 2 reactors, including either 4 or 8 processing stations,for the polyimide deposition and etch back; and 2 reactors, includingeither 4 or 8 processing stations, for the selective dielectricdeposition.

Referring to FIG. 16, an apparatus 100 is provided for conductingpolymer deposition and organic material etch back in situ. The apparatus100 includes a reaction chamber defines a reaction space 115 configuredto accommodate at least one substrate 120. The apparatus 100 alsoincludes a first reactant vessel 105 configured for vaporizing a firstorganic reactant 110 to form a first reactant vapor. A gas line 130fluidly connects the first reactant vessel 105 to a reaction space 115within which a substrate 120 can be accommodated. The gas line 130 isconfigured to selectively transport the first reactant vapor from thefirst reactant vessel 105 to an inlet manifold 135 to the reaction space115. The apparatus 100 also includes a second reactant vessel 140holding a second reactant 145. In some embodiments, the second reactant145 is naturally in a gaseous state; in other embodiments, the secondreactant vessel 140 is also configured to vaporize the second reactant145 from a natural liquid or solid state. The second reactant vessel 140is in selective fluid communication with the inlet manifold 135. Theinlet manifold 135 can include a shared distribution plenum across thechamber width, in a showerhead or cross-flow configuration, or canmaintain separate paths to the reaction space 120 for separatereactants. For sequential deposition embodiments, it can be desirable tokeep the reactant inlet paths separate until introduction to thereaction space 115 in order to avoid reactions along the surface ofcommon flow paths for multiple reactants, which can lead to particlegeneration. The apparatus can in some embodiments include additionalvessels for supply of additional reactants.

The illustrated apparatus 100 also includes a plasma source 147.Although illustrated schematically as if attached to the reaction space115, the skilled artisan will appreciate that the plasma source maybe bea remote plasma source external to the reaction space 115, or may be anin situ plasma generator for direct plasma generation (e.g.,capacitively coupled) within the reaction space 115. Alternatively oradditionally, an ozone generator may be employed for removal of organicmaterial, as described below with respect to FIGS. 24-25 (e.g., forpartial etch back after selective deposition of organic material, forremoval of an organic passivation layer, and/or for chamber cleaning).

One or more additional gas source(s) 150 is (are) in selective fluidcommunication with the first reactant vessel 105, the reaction space 115and the plasma source 147 (to the extent separate from the reactionspace 115). The gas source(s) 150 can include inert gases that can serveas purge and carrier gases, and other gases (e.g., Ar/H₂) for plasmaetch back. Inert gas supply from the gas source(s) can also be inselective fluid communication with the second reactant vessel 140, asshown, and any other desired reactant vessels to serve as a carrier gas.

A control system 125 communicates with valves of the gas distributionsystem in accordance with organic passivation layer deposition and etchback methods and described herein. The control system 125 typicallyincludes at least one processor and a memory programmed for desiredprocessing. For sequential deposition processing, the valves areoperated in a manner that alternately and repeatedly exposes thesubstrate to the reactants, whereas for simultaneous supply of thereactants in a conventional CVD process, the valves can be operated tosimultaneously expose the substrate to mutually reactive reactants.

An exhaust outlet 155 from the reaction space 115 communicates throughan exhaust line 160 with a vacuum pump 165. The control system 125 isconfigured to operate the vacuum pump 165 to maintain a desiredoperational pressure and exhaust excess reactant vapor and byproductthrough the exhaust outlet 155.

The control system 125 can also control pressure and temperature invarious components of the apparatus 100. For example, the control systemcan be programmed to keep the substrate 120 at a suitable temperaturefor the processes being performed. In one embodiment, control system 125is also configured to maintain the first reactant 110 in the firstreactant vessel 105 at a temperature A, and is configured to maintainthe substrate 120 in the reaction space 115 at a temperature B, wherethe temperature B is lower than the temperature A. In an embodiment, thecontrol system 125 or a separate temperature control is also configuredto maintain the gas line 130 at a temperature C, where the temperature Cis higher than the temperature A.

Accordingly, the apparatus 100 includes source vessels 105, 140 forvaporizing and supplying the reactants described above for polymerdeposition (e.g., one vessel for a diamine and one vessel for adianhydride precursor). The plasma source 147 communicates with gassource(s) 150 that include a source of H₂ and inert gas (e.g., noblegas, particularly argon). Additionally, the apparatus 100 includes acontrol system 125 programmed to supply gases and operate the plasmasource in a manner to perform the polymer deposition described herein,as well as a hydrogen plasma etch back. The control system 125preferably maintains the substrate 120 in a range of 180° C. to 220° C.,more particularly about 190° C. to 210° C., such that the polymerdeposition and etch back can be conducted at the same temperaturesequentially, without removing the substrate 120 from the reaction space115. The etch back may be from 1-20 seconds, particularly from 5-15seconds. As an example, a 10 second etch using Ar/H₂ plasma at 200° C.was found to give ˜4.5 nm etching of a polyimide layer. As anotherexample, a pulsed ozone (O₃) etch process may be used for the etch backprocess, similar to the high O₃ concentration etch process for removalof the passivation layer and chamber cleaning as described below withreference FIGS. 24 and 25. As the skilled artisan will appreciate,process conditions may be modified for slower and more controlledetching for the purpose of partial etch back to minimize overetching ofthe desired passivation layer on the first surface. For example pulsedurations can be lowered, or a single pulse may suffice, O₃concentration can be lowered, and/or temperatures can be loweredrelative to the polymer removal process described below with respect toFIG. 24. For example, the 125° C. process of FIG. 24 may be sufficientmild to serve for the partial etch back of any organic material from thesurface on which organic material is to be minimized. Indeed, FIG. 25demonstrates how etch rate depends strongly upon etch temperature for O₃etching of polymer. Combining the selective deposition of thepassivation layer with the partial etch back would not increase processtime of the single chamber much, as the etch process is typically veryshort.

The same equipment and etchants can also be used for removal of thepassivation layer. For example, a high O₃ concentration etch process maybe used, wherein the high O₃ concentration etch process is performed at9 Torr, with 1 sec pulse/1 sec purge of O₃, an O₃ flow of 750 sccm, andan N₂ dilution flow of 1.2 slm, at 125° C. was found to give ˜0.3 nm/minetching of a polyimide layer, as seen in FIG. 24. As an example, a high03 concentration etch process may be used, wherein the high O₃concentration etch process is performed at 9 Torr, with 1 sec pulse/1sec purge of O₃, an O₃ flow of 750 sccm, and an N₂ dilution flow of 1.2slm, at 150° C. was found to give ˜2.4 nm/min etching of a polyimidelayer, as seen in FIG. 24. An activation energy of ˜0.4 eV wascalculated for a polyimide layer etch using O₃/N₂ from the graph shownin FIG. 24, as shown in the Arrhenius plot FIG. 25.

Ar/H₂ plasma or O₃ etching could also be used as a chamber etch to keepthe reaction space 115 clean. As an example, a chamber etch wasperformed in an ASM Pulsar 3000 chamber with about 48 hours of O₃/N₂exposure with an O₃ flow of 1.2 slm, inner chamber pressure of about 9Torr, an O₂ flow of 1 slm (i.e., 2.5 V), N₂ flow of 0.020 slm (0.5V) andO₃ concentration set point of 250 g/Nm3 (power about 24% of the maximumvalue). The processing time for such a chamber etch may be shortened byoptimizing the O₃ concentration and the O₃ injection point into thechamber.

The apparatus 100 configured for polymer deposition and etch back, couldbe a showerhead reactor with solid source vessels for DAH (with avaporization temperature of about 40° C.) and PMDA (with vaporizationtemperature of about 170° C.). In one embodiment, the plasma source 147comprises an in situ direct plasma (e.g., capacitively coupled)apparatus with argon and H₂ supply for the in situ etch back. In anotherembodiment, the apparatus 100 may be a cross-flow reactor rather than ashowerhead reactor, but still having the above-noted with solid sourcevessels 105, 140 and direct plasma capability. In another embodiment,the plasma source 147 comprises a remote plasma is coupled to thereaction space 115 to supply plasma produces from an Ar/H₂ plasma. Inanother embodiment, the plasma source 147 could be replaced with anozone generator coupled to the reaction space 115. The remote plasma orozone generator could, for example, be connected to a showerheadreactor.

The polymer deposition apparatus 100 desirably includes self-cleaningcapability to keep the reaction space 115 and exhaust lines 160 cleanafter multiple depositions. In some embodiments, the in situ or remoteAr/H₂ plasma source 147 noted above for etch back can be adapted forperiodic chamber cleaning, possibly under higher power or temperatures,as it can operate in the absence of production substrates and onlyperiodically (rather than every wafer). Alternatively, the polymerdeposition chamber can be provided with a remote plasma supplied withNF₃ etch, or an ozone supply to conduct periodic chamber cleans, asdescribed above with respect to FIGS. 24 and 25. In some embodiments, anO₃/N₂ supply can be adapted for periodic chamber cleaning, possiblyunder higher power or temperatures compared to the polymer partial etchback or removal processes, as the chamber clean process operates in theabsence of production substrates and only periodically (rather thanevery wafer).

Line Edge Position

Referring to FIG. 17 and in some embodiments, as described above,selective deposition on a second surface can be accomplished byselective passivation of a first surface following selective depositionof a dielectric, such as ZrO₂, on the second surface. In the illustratedflow chart, the first surface can be metallic (e.g, an embedded metalfeature in an integrated circuit interlevel dielectric, or ILD), and thesecond surface can be dielectric (e.g., the ILD). The passivation cancomprise a polymer or other organic material selectively deposited onthe first surface relative to the second surface of a part in Step 1.Subsequently, a polymer etch back, sometimes referred to as a “clean-up”etch to perfect the selectivity, is performed to remove polymer that mayhave deposited on the second surface in Step 2, without removing all ofthe polymer from the first surface. As the polymer acts as a passivationlayer, a dielectric material is selectively deposited on the secondsurface in Step 3. Any number of suitable dielectric materials may beused in Step 3. In some embodiments, the dielectric material may beselected from ZrO₂ and other metal oxides, such as transition metaloxides or aluminum oxide, or other dielectric oxides including mixtureshaving etch selectivity over SiO₂-based materials or slow etch rate inconditions in which SiO₂-based materials are etched. Even though somesuch metal oxides may have high k values, particularly higher than 5 oreven higher than 10, they are thin, are located in positions that avoidsignificant parasitic capacitance in metallization structures, andadvantageously allow for masking surfaces against selective etching ofsilicon oxide materials. In other embodiments, the dielectric can be asilicon oxide based material, but may be thicker to serve as an etchmask as described herein. In Step 4 of FIG. 17, the polymer passivationis removed from the first surface.

FIG. 18 illustrates the effect that etch back time for removal of thepassivation (e.g., polymer or other organic layer) from the secondsurface has on the dielectric layer formed. More specifically, theposition of the edge of the selectively formed dielectric layer can becontrolled relative to the boundary between the underlying metallic anddielectric surfaces by selecting the extent of the intermediate polymeretch back process. In an embodiment, polymer is deposited on the firstsurface relative to the second surface of a part, as describedpreviously in Step 1 of FIG. 17, as seen in the 1^(st) row ofillustrations in FIG. 18. As seen in the polymer as depositedillustration, preferential deposition of the polymer on the firstsurface creates a thicker polymer layer surface over the first surface,with a relatively thin polymer layer over the second surface,consequently having a downwardly sloped polymer thickness from the firstsurface to the second surface at the first-second surface boundary.Subsequently, a polymer etch back, as described previously in Step 2 ofFIG. 17, may be performed for varying durations (or for the samedurations with different etch rates, such as by different temperaturesor etchant concentrations, or for different durations and different etchrates) to control the thickness and shape of the polymer layer, as seenin the 2^(nd) through 6^(th) rows of the first column of illustrationsin FIG. 18. The etch back may be isotropic or anisotropic. In someembodiments, a polymer etch time is minimal and the polymer etch doesnot remove sufficient polymer to expose the second surface, as seen inthe 2^(nd) row of illustrations in FIG. 18. In this case, the subsequentselective dielectric deposition does not work because both the first andsecond surfaces are covered with the passivation layer, and even if asmall amount of dielectric deposits it will be removed by a lift-offprocess with removal of the passivation layer. In some embodiments, apolymer etch time is selected to remove the majority of the polymerformed from the second surface, but leave a polymer layer leading edgethat extends over the first-second surface boundary onto the secondsurface, as seen in the 3^(rd) row of illustrations in FIG. 18. In thiscase, subsequent selective deposition of the dielectric and removal ofthe polymer leaves a gap between the deposited dielectric edge and thefirst-second surface boundary. In some embodiments, a polymer etch timeis selected to remove the polymer from the second surface, and a polymerlayer edge is left aligned with the first-second surface boundary, asseen in the 4^(th) row of illustrations in FIG. 18. In this case,subsequent selective deposition of the dielectric and removal of thepolymer leaves the bottom surface edge of deposited dielectric alignedwith the first-second surface boundary. In some embodiments, a polymeretch time is selected to remove the polymer from the second surface anda portion of the polymer from the first surface, and a first gap existsbetween a polymer layer leading edge and first-second surface boundary,as seen in the 5^(th) row of illustrations in FIG. 18. In this case,subsequent selective deposition of the dielectric and removal of thepolymer leaves the deposited dielectric extending over the first-secondsurface boundary and overlapping with the first surface. If the polymeretch time is performed for an extended period of time and the polymeretch completely removes the polymer from both the first surface and thesecond surface, as seen in the 6^(th) row of illustrations in FIG. 18,then subsequent dielectric deposition is not selective.

Thus, selective dielectric selective deposition and partial polymer etchback, as described previously in Steps 3 and 4 of FIG. 17, may beperformed to create various relationships between the edge of theselectively deposited dielectric layer on the second surface and theinterface between the first and second surfaces, depending on the extentof the passivation etch back following its selective deposition, as seenin the right-most images of the 2^(nd) through 6^(th) rows of the thirdcolumn of illustrations in FIG. 17. In some embodiments, no dielectriclayer is formed because the polymer layer passivated the second surface,as seen in the 2^(nd) row of illustrations in FIG. 18. In someembodiments, a gap exists between a dielectric on the second surfacefirst surface, as seen in the 3^(rd) row of illustrations in FIG. 18. Insome embodiments, the dielectric layer edge is aligned with thefirst-second surface boundary, as seen in the 4^(th) row ofillustrations in FIG. 18. In some embodiments, the dielectric layeroverlaps the first surface, as seen in the 5^(th) row of illustrationsin FIG. 18. In some arrangements, the dielectric layer forms on both thefirst surface and the second surface because no polymer layer passivatedthe first surface, as seen in the 6^(th) row of illustrations in FIG.18.

FIG. 19 illustrates the effect that passivation layer depositionthickness has on the dielectric layer formed. More specifically, theposition of the edge of the selectively formed dielectric layer can becontrolled relative to the boundary between the underlying metallic anddielectric surfaces by selecting the thickness of the intermediatepolymer passivation layer. As passivation layer deposition thicknessincreases, the passivation layer thicknesses on both the first surfaceand second surface are increased. However, because the passivation layeris selectively deposited on the first surface, the passivation thicknessover the second surface increases less than the passivation layerthickness over the first surface. Therefore, a passivation etch back,dielectric deposition and passivation removal will create selectivedielectric layers with varying positions relative to the first-secondsurface boundary. In some embodiments, a passivation layer is depositedwhich produces a gap between a selectively deposited dielectric layeredge and the first-second surface boundary, as seen in as seen in the1^(st) column of illustrations in FIG. 19. In some embodiments, athicker polymer layer is deposited which produces a larger gap between aselectively deposited dielectric layer edge and the first surface, asseen in as seen in the 2^(nd) column of illustrations in FIG. 19.

FIG. 20 illustrates the effect selectively deposited dielectricthickness has on the relative positions of the dielectric layer formedand the first-second surface boundary. More specifically, the positionof the edge of the selectively formed dielectric layer can be controlledrelative to the boundary between the underlying metallic and dielectricsurfaces by selecting the thickness of the selective dielectric layer.As dielectric deposition thickness selectively deposited on the secondsurface increases, the dielectric overhang edge increasingly extendsfurther past the first-second surface boundary. In some embodiments, adielectric layer is deposited which produces a certain overhangstructure, as seen in as seen in the 1^(st) column of illustrations inFIG. 20. In some embodiments, a thicker dielectric layer is depositedwhich produces a greater overhang, as seen in as seen in the 2^(nd)column of illustrations in FIG. 20. In some embodiments, an even thickerdielectric layer is deposited which produces an even greater dielectricoverhang over the first surface, as seen in as seen in the 3^(rd) columnof illustrations in FIG. 20. For certain subsequent processes, such asanisotropic processing (e.g., anisotropic reactive ion etching), theextent of the overhang can shadow portions of the first surface andprotect against the subsequent processing.

Thus, in some embodiments, though largely selectively formed over thedielectric surface similar to FIG. 1D, the dielectric layer isselectively deposited to produce an overhang and/or overlap with themetallic feature. In some embodiments, the dielectric layer does notcomprise an overhang or overlap, and the edge of the selectivelydeposited dielectric on dielectric can be aligned with the edge of themetallic feature or there can be a gap between the edge of theselectively deposited dielectric layer and the metallic feature. Becauseof the selective deposition techniques taught herein, the selectivelydeposited dielectric layer may have features characteristic of selectivedeposition, without the use of traditional masking and etching topattern the dielectric layer. For example, the edge of the dielectriclayer may be tapered with a slope of less than 45 degrees, rather thanhaving a vertical or steeply sloped sidewall, as is typical ofphotolithographically patterned layers. This characteristic etch profilemay remain whether or not the selectively deposited layer was subjectedto a clean-up etch, or partial etch back.

FIGS. 21A-21D illustrate how topography can affect the relationshipbetween a selectively deposited dielectric and the boundary betweenfirst and second surfaces

FIG. 21A illustrates a planar structure that results in an edge of aselectively deposited dielectric 2502 being aligned with thefirst-second surface boundary. The first surface that is passivated by apassivation layer 2504, for example a polymer material, can be definedby a metallic material, such as embedded metal 2506, and the secondsurface can be defined by a low k dielectric, such as an interleveldielectric (ILD) 2508. The passivation layer 2504 is selectivelydeposited over the first surface and the dielectric layer 2502 isselectively deposited over the second surface, wherein the edge of thedielectric layer 2502 is aligned with the first-second surface boundary.

FIG. 21B illustrates a recessed first surface relative to the secondsurface. As above, the first surface can comprise a metallic material2506 embedded and recessed with in a low k dielectric material 2508 thatdefines the second surface. The passivation layer 2504 is selectivelyformed over the first surface within the recess. The dielectric layer2502 is disposed over the second surface and over the recess walls,wherein the edge of the dielectric layer 2502 meets the surface of thepassivation layer 2504. Removal of the passivation layer 2504 willresult in the dielectric layer 2502 selectively formed on the secondsurface but overlapping with the first surface (e.g., metallic feature2506).

FIG. 21C illustrates an elevated first surface with respect to thesecond surface. The first surface can be defined by a metallic material2506 embedded in and protruding above the second surface, which can be alow k dielectric material 2508. The passivation layer 2504 is disposedover the first surface, including protruding side walls, and thus atleast partially disposed over the second surface. The dielectric layer2502 is disposed over the second surface but is spaced from the firstsurface by the thickness of the passivation material 2504 on the sidewalls. Thus, after removal of the passivation layer 2504, there is a gapbetween the dielectric layer 2502 and the first surface (e.g.,protruding metallic feature 2606)

FIG. 21D illustrates a recessed first surface of some embodiments,similar to FIG. 21B but with a thicker passivation layer 2504 fillingthe recess. In this case, after removal of the passivation layer 2504, agap is left between the selectively deposited dielectric layer 2502 onthe second surface and the first surface. In this case, the gap takesthe form of a vertical sidewall of the second surface, which is thenexposed to subsequent processing.

Thus, FIGS. 18-21D illustrate variables that can be adjusted to tune theposition of a selectively deposited dielectric 2502 (e.g., on dielectricsecond surface) relative to an interface between the first and secondsurfaces (e.g., between a metallic feature 2506 and low k dielectric2508). In particular, FIG. 18 shows how extent or time for passivationlayer etch back can affect the relative positions; FIG. 19 shows howthickness of the selectively deposited passivation layer can affect therelative positions; FIG. 20 shows how thickness of the selectivelydeposited dielectric layer can affect the relative positions; and FIGS.21A-21D show how topography of the first and second surfaces can affectthe relative positions. These variables can thus be adjusted to affectwhether the selectively deposited dielectric on the second surface isaligned with, has a gap relative to, or overlaps the first surface.

Example Applications

FIGS. 22A-22E illustrate a device and process of creating a device, insome embodiments, with improved electrical isolation. FIG. 22Aillustrates a partially fabricated integrated circuit with an embeddedmetallic feature 2606 that defines a first surface which is flush with asecond surface, defined by the surrounding low k material 2608, similarto the planar structure shown in FIG. 21A. The metallic featurecomprises a first material further comprising Cu 2610 and TaN barriermaterial 2612 positioned within a first low-k dielectric material 2608.

FIG. 22B illustrates the device of FIG. 22A subsequent to a conductivebarrier layer 2614 over the first material. In some embodiments, thebarrier layer 2614 may be W. While illustrated as protruding, in someembodiments the barrier material 2614 over the Cu 2610 line or via maybe embedded in and flush with the surrounding low k material 2608.

FIG. 22C illustrates the device of FIG. 22B subsequent to the selectivedeposition of a passivation layer 2604 over the first surface nowdefined by the metallic barrier layer 2614 (W), wherein edges of thefirst surface are exposed. In some embodiments, the passivation layer2604 may be an organic material, such as a polymer. In some embodiments,the selective deposition of the passivation layer 2604 is followed by anetch back of the passivation layer material sufficient to expose some ofthe metallic first surface.

FIG. 22D illustrates the device of FIG. 22C subsequent to the selectivedeposition of a dielectric layer 2602 over the second surface,overlapping with the metallic first surface. In some embodiments, thedielectric layer 2602 may be a high-k material. In some embodiments, thehigh-k material may be ZrO₂. In some embodiments, the selectivedielectric layer 2602 may be a low-k material, such as SiOC, Al₂O₃, andSiN. In some embodiments, the selectively deposited dielectric material2602 may serve as an etch stop with respect to subsequent etches throughlow k material 2608 to open trenches or vias that expose the metallicbarrier material 2614.

FIG. 22E illustrates the device of FIG. 22D subsequent to removal of thepolymer passivation layer 2604, thereby exposing the underlying metallayer surface (of barrier material 2614 in this case). The selectivedielectric 2602 overlaps the metallic first surface defined by barrierlayer 2614 and reduces the risk of shorting when a subsequent metallicfeature (e.g., overlying metal line or via) is formed thereover. Inparticular, a low k material is deposited over the structure of FIG.22E, and openings are created and filled with metal. The openings arecreated by masking and selective low k etching, and the etch stops onthe selectively deposited dielectric (e.g., ZrO₂). The overlap of theselectively deposited dielectric 2602 with the metallic feature definedby the barrier layer 2614, resulting from the selection of conditionsduring the passivation, etch-back, dielectric deposition and/ortopography, protects against misalignment. Thus the overlap preventscontact with adjacent metallic features or undesired etching of thelower low k material 2608. Note that the selectively depositeddielectric material 2602 can stay in the final integrated circuitdevice, having served as an etch stop between ILD layers. Althoughordinarily high k materials are avoided in metallization processes,parasitic capacitance is minimal. Minimal parasitic capacitance is dueto the predominant position of the high k material over the low kmaterial, the thinness of the high k material due to its functions, andthe advantage of high selectivity for this dielectric capping layer overhigh k material outweighs slight parasitic capacitance introduced by thematerial selection. Of course, high etch selectivity may also beachieved with lower k materials to be selectively deposited on the ILD.

FIGS. 23A-23B illustrate a device and process of creating a device, insome embodiments, with air-gaps, which may be desirable for a variety ofreasons, such as reduction of parasitic capacitance between closelyspaced metallic features (e.g., metal lines) in an integrated circuit.FIG. 23A illustrates planar surface of a partially fabricated integratedcircuit of some embodiments, similar to the device previously shown inFIG. 21A. The initial structure may be a first surface defined by ametallic feature 2706 (e.g., Cu line with dielectric and barrier liners)surrounded by a second surface defined by dielectric material 2608(e.g., low k ILD). A passivation layer 2704 is selectively depositedover the first surface, and an etch back performed to expose the secondsurface in a manner that leaves the passivation layer 2704 over thefirst surface and partially over the second surface. A dielectric 2702is selectively deposited over the second surface, wherein the dielectriclayer edge is spaced away from the first-second surface boundary ontothe second surface. FIG. 23B illustrates the device of FIG. 23Asubsequent to the removal of the passivation layer 2704 to expose thefirst surface and partially expose the second surface previously coveredby the first material, leaving a gap 2710 between the selectivelydeposited dielectric material and the first surface (metallic feature2706). Subsequently selectively etching the exposed second materialforms cavities 2712 in those gaps 2710 next to the metallic features. Insome embodiments, the second material that is selectively etched is SiO.In some embodiments, selective etching is an HBr dry etch. An HBr dryetch can selectively etch silicon oxide at about 6-8 nm/min, whereascertain other materials are etched at lower rates such as siliconnitride (<0.3 nm/min) and zirconium oxide (<0.3 nm/min), and likely willnot etch tungsten without chlorine (e.g., Cl₂) or sulfur hexafluoride(e.g., SF₆). Deposition of a third material 2714, such as standard low kmaterial, with sufficiently low conformality leaves air-gaps 2716 withinthe low k material 2708 adjacent to a lateral sides of the metallicfeatures 2706. As is known in the art, the air cavities lower theoverall k value of the ILD and reduce parasitic capacitance betweenmetallic features.

Although certain embodiments and examples have been discussed, it willbe understood by those skilled in the art that the scope of the claimsextend beyond the specifically disclosed embodiments to otheralternative embodiments and/or uses and obvious modifications andequivalents thereof.

What is claimed is:
 1. A method of selective deposition on a secondsurface of a part relative to a first surface of the part, where thefirst and second surfaces have different compositions, the methodcomprising: selectively forming a passivation layer comprising a polymerfrom vapor phase reactants on the first surface while leaving the secondsurface without the passivation layer, wherein the first surfacecomprises an inorganic dielectric and the second surface comprisesmetallic material; and selectively depositing a structural layer fromvapor phase reactants on the second surface relative to the passivationlayer.
 2. The method of claim 1, wherein the structural layer comprisesa metal.
 3. The method of claim 2, further comprising selectivelydepositing a dielectric layer on the structural layer relative to thepassivation layer.
 4. The method of claim 1, wherein selectively formingthe passivation layer is performed without catalytic agents on the firstsurface.
 5. The method of claim 1, wherein selectively forming thepassivation layer comprises depositing polyimide.
 6. The method of claim1, wherein selectively forming the passivation layer comprises forming apassivation blocking layer on the second surface and subsequentlyselectively vapor depositing the passivation layer on the first surfacerelative to the passivation blocking layer.
 7. The method of claim 6,wherein forming the passivation blocking layer comprises forming aself-assembled monolayer on the second surface.
 8. The method of claim7, wherein forming the passivation blocking layer comprises contactingthe second surface with a sulfur-containing monomer.
 9. The method ofclaim 6, further comprising removing the passivation blocking layer fromthe second surface without removing the passivation layer from the firstsurface and subsequently selectively depositing the structural layer onsecond surface relative to the passivation layer.
 10. The method ofclaim 9, wherein removing the passivation blocking layer comprisesheating to a temperature that removes the passivation blocking layerwithout removing the passivation layer.
 11. The method of claim 1,further comprising selectively removing the passivation layer from thefirst surface after selectively depositing the structural layer on thesecond surface without removing the structural layer, wherein thepassivation layer is deposited directly on the first surface, andwherein material of the first surface on which the passivation layer isdirectly deposited remains after selectively removing the passivationlayer.
 12. A method of selective deposition on a second surface of apart relative to a first surface of the part, where the first and secondsurfaces have different compositions, the method comprising: selectivelyforming a passivation layer comprising a polymer on the first surfacerelative to the second surface, wherein selectively forming comprisesalternately and sequentially exposing the first and second surfaces tofirst and second vapor phase reactants, and wherein selectively formingleaves the second surface without the passivation layer; and selectivelydepositing a structural layer from vapor phase reactants on the secondsurface relative to the passivation layer.
 13. The method of claim 12,wherein the first surface comprises an inorganic dielectric material andthe second surface comprises a metallic material.
 14. The method ofclaim 13, wherein selectively forming the passivation layer comprisesforming a passivation blocking layer on the second surface andsubsequently selectively vapor depositing the passivation layer on thefirst surface relative to the passivation blocking layer.
 15. The methodof claim 12, wherein selectively forming the passivation layer comprisesselective atomic layer deposition.
 16. The method of claim 12, whereinselectively forming the passivation layer further comprises depositing alarger amount of passivation layer on the first surface than the secondsurface, and wherein selectively forming further comprises etching anypolymer from the second surface while leaving at least some polymer onthe first surface.
 17. The method of claim 12, wherein the structurallayer overlaps with the first surface.
 18. A method of selectivedeposition on a second surface of a part relative to a first surface ofthe part, where the first and second surfaces have differentcompositions, the method comprising: selectively forming a passivationlayer comprising a polymer from vapor phase reactants directly on thefirst surface without catalytic agents on the first surface whileleaving the second surface without the passivation layer; selectivelydepositing a structural layer from vapor phase reactants on the secondsurface relative to the passivation layer; and selectively removing thepassivation layer from the first surface without removing the structurallayer after selectively depositing the structural layer, whereinmaterial of the first surface on which the passivation layer wasdirectly deposited remains after selectively removing the passivationlayer.
 19. The method of claim 18, wherein the first surface comprisesan inorganic dielectric material and the second surface comprises ametallic material.
 20. The method of claim 18, wherein the first surfacecomprises a metallic surface and the second surface comprise aninorganic dielectric material.